class Sequel::Database

A Database object represents a virtual connection to a database. The Database class is meant to be subclassed by database adapters in order to provide the functionality needed for executing queries.

Constants

OPTS

1 - Methods that execute queries and/or return results

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Constants

COLUMN_SCHEMA_DATETIME_TYPES
COLUMN_SCHEMA_STRING_TYPES

Attributes

cache_schema[RW]

Whether the schema should be cached for this database. True by default for performance, can be set to false to always issue a database query to get the schema.

prepared_statements[R]

The prepared statement object hash for this database, keyed by name symbol

Public Instance Methods

<<(sql) click to toggle source

Runs the supplied SQL statement string on the database server. Returns self so it can be safely chained:

DB << "UPDATE albums SET artist_id = NULL" << "DROP TABLE artists"
   # File lib/sequel/database/query.rb
25 def <<(sql)
26   run(sql)
27   self
28 end
call(ps_name, hash=OPTS, &block) click to toggle source

Call the prepared statement with the given name with the given hash of arguments.

DB[:items].where(id: 1).prepare(:first, :sa)
DB.call(:sa) # SELECT * FROM items WHERE id = 1
   # File lib/sequel/database/query.rb
35 def call(ps_name, hash=OPTS, &block)
36   prepared_statement(ps_name).call(hash, &block)
37 end
execute_ddl(sql, opts=OPTS, &block) click to toggle source

Method that should be used when submitting any DDL (Data Definition Language) SQL, such as create_table. By default, calls execute_dui. This method should not be called directly by user code.

   # File lib/sequel/database/query.rb
42 def execute_ddl(sql, opts=OPTS, &block)
43   execute_dui(sql, opts, &block)
44 end
execute_dui(sql, opts=OPTS, &block) click to toggle source

Method that should be used when issuing a DELETE or UPDATE statement. By default, calls execute. This method should not be called directly by user code.

   # File lib/sequel/database/query.rb
49 def execute_dui(sql, opts=OPTS, &block)
50   execute(sql, opts, &block)
51 end
execute_insert(sql, opts=OPTS, &block) click to toggle source

Method that should be used when issuing a INSERT statement. By default, calls execute_dui. This method should not be called directly by user code.

   # File lib/sequel/database/query.rb
56 def execute_insert(sql, opts=OPTS, &block)
57   execute_dui(sql, opts, &block)
58 end
get(*args, &block) click to toggle source

Returns a single value from the database, see Dataset#get.

DB.get(1) # SELECT 1
# => 1
DB.get{server_version.function} # SELECT server_version()
   # File lib/sequel/database/query.rb
65 def get(*args, &block)
66   @default_dataset.get(*args, &block)
67 end
run(sql, opts=OPTS) click to toggle source

Runs the supplied SQL statement string on the database server. Returns nil. Options:

:server

The server to run the SQL on.

DB.run("SET some_server_variable = 42")
   # File lib/sequel/database/query.rb
74 def run(sql, opts=OPTS)
75   sql = literal(sql) if sql.is_a?(SQL::PlaceholderLiteralString)
76   execute_ddl(sql, opts)
77   nil
78 end
schema(table, opts=OPTS) click to toggle source

Returns the schema for the given table as an array with all members being arrays of length 2, the first member being the column name, and the second member being a hash of column information. The table argument can also be a dataset, as long as it only has one table. Available options are:

:reload

Ignore any cached results, and get fresh information from the database.

:schema

An explicit schema to use. It may also be implicitly provided via the table name.

If schema parsing is supported by the database, the column information hash should contain at least the following entries:

:allow_null

Whether NULL is an allowed value for the column.

:db_type

The database type for the column, as a database specific string.

:default

The database default for the column, as a database specific string, or nil if there is no default value.

:primary_key

Whether the columns is a primary key column. If this column is not present, it means that primary key information is unavailable, not that the column is not a primary key.

:ruby_default

The database default for the column, as a ruby object. In many cases, complex database defaults cannot be parsed into ruby objects, in which case nil will be used as the value.

:type

A symbol specifying the type, such as :integer or :string.

Example:

DB.schema(:artists)
# [[:id,
#   {:type=>:integer,
#    :primary_key=>true,
#    :default=>"nextval('artist_id_seq'::regclass)",
#    :ruby_default=>nil,
#    :db_type=>"integer",
#    :allow_null=>false}],
#  [:name,
#   {:type=>:string,
#    :primary_key=>false,
#    :default=>nil,
#    :ruby_default=>nil,
#    :db_type=>"text",
#    :allow_null=>false}]]
    # File lib/sequel/database/query.rb
121 def schema(table, opts=OPTS)
122   raise(Error, 'schema parsing is not implemented on this database') unless supports_schema_parsing?
123 
124   opts = opts.dup
125   tab = if table.is_a?(Dataset)
126     o = table.opts
127     from = o[:from]
128     raise(Error, "can only parse the schema for a dataset with a single from table") unless from && from.length == 1 && !o.include?(:join) && !o.include?(:sql)
129     table.first_source_table
130   else
131     table
132   end
133 
134   qualifiers = split_qualifiers(tab)
135   table_name = qualifiers.pop
136   sch = qualifiers.pop
137   information_schema_schema = case qualifiers.length
138   when 1
139     Sequel.identifier(*qualifiers)
140   when 2
141     Sequel.qualify(*qualifiers)
142   end
143 
144   if table.is_a?(Dataset)
145     quoted_name = table.literal(tab)
146     opts[:dataset] = table
147   else
148     quoted_name = schema_utility_dataset.literal(table)
149   end
150 
151   opts[:schema] = sch if sch && !opts.include?(:schema)
152   opts[:information_schema_schema] = information_schema_schema if information_schema_schema && !opts.include?(:information_schema_schema)
153 
154   Sequel.synchronize{@schemas.delete(quoted_name)} if opts[:reload]
155   if v = Sequel.synchronize{@schemas[quoted_name]}
156     return v
157   end
158 
159   cols = schema_parse_table(table_name, opts)
160   raise(Error, "schema parsing returned no columns, table #{table_name.inspect} probably doesn't exist") if cols.nil? || cols.empty?
161 
162   primary_keys = 0
163   auto_increment_set = false
164   cols.each do |_,c|
165     auto_increment_set = true if c.has_key?(:auto_increment)
166     primary_keys += 1 if c[:primary_key]
167   end
168 
169   cols.each do |_,c|
170     c[:ruby_default] = column_schema_to_ruby_default(c[:default], c[:type]) unless c.has_key?(:ruby_default)
171     if c[:primary_key] && !auto_increment_set
172       # If adapter didn't set it, assume that integer primary keys are auto incrementing
173       c[:auto_increment] = primary_keys == 1 && !!(c[:db_type] =~ /int/io)
174     end
175     if !c[:max_length] && c[:type] == :string && (max_length = column_schema_max_length(c[:db_type]))
176       c[:max_length] = max_length
177     end
178   end
179   schema_post_process(cols)
180 
181   Sequel.synchronize{@schemas[quoted_name] = cols} if cache_schema
182   cols
183 end
table_exists?(name) click to toggle source

Returns true if a table with the given name exists. This requires a query to the database.

DB.table_exists?(:foo) # => false
# SELECT NULL FROM foo LIMIT 1

Note that since this does a SELECT from the table, it can give false negatives if you don't have permission to SELECT from the table.

    # File lib/sequel/database/query.rb
193 def table_exists?(name)
194   sch, table_name = schema_and_table(name)
195   name = SQL::QualifiedIdentifier.new(sch, table_name) if sch
196   ds = from(name)
197   transaction(:savepoint=>:only){_table_exists?(ds)}
198   true
199 rescue DatabaseError
200   false
201 end

Private Instance Methods

_metadata_dataset() click to toggle source

Uncached version of metadata_dataset, designed for overriding.

    # File lib/sequel/database/query.rb
291 def _metadata_dataset
292   dataset
293 end
_table_exists?(ds) click to toggle source

Should raise an error if the table doesn't not exist, and not raise an error if the table does exist.

    # File lib/sequel/database/query.rb
207 def _table_exists?(ds)
208   ds.get(SQL::AliasedExpression.new(Sequel::NULL, :nil))
209 end
column_schema_default_string_type?(type) click to toggle source

Whether the type should be treated as a string type when parsing the column schema default value.

    # File lib/sequel/database/query.rb
213 def column_schema_default_string_type?(type)
214   COLUMN_SCHEMA_STRING_TYPES.include?(type)
215 end
column_schema_default_to_ruby_value(default, type) click to toggle source

Transform the given normalized default string into a ruby object for the given type.

    # File lib/sequel/database/query.rb
219 def column_schema_default_to_ruby_value(default, type)
220   case type
221   when :boolean
222     case default 
223     when /[f0]/i
224       false
225     when /[t1]/i
226       true
227     end
228   when :string, :enum, :set, :interval
229     default
230   when :blob
231     Sequel::SQL::Blob.new(default)
232   when :integer
233     Integer(default)
234   when :float
235     Float(default)
236   when :date
237     Sequel.string_to_date(default)
238   when :datetime
239     DateTime.parse(default)
240   when :time
241     Sequel.string_to_time(default)
242   when :decimal
243     BigDecimal(default)
244   end
245 end
column_schema_max_length(db_type) click to toggle source

Look at the db_type and guess the maximum length of the column. This assumes types such as varchar(255).

    # File lib/sequel/database/query.rb
277 def column_schema_max_length(db_type)
278   if db_type =~ /\((\d+)\)/
279     $1.to_i
280   end
281 end
column_schema_normalize_default(default, type) click to toggle source

Normalize the default value string for the given type and return the normalized value.

    # File lib/sequel/database/query.rb
249 def column_schema_normalize_default(default, type)
250   if column_schema_default_string_type?(type)
251     return unless m = /\A'(.*)'\z/.match(default)
252     m[1].gsub("''", "'")
253   else
254     default
255   end
256 end
column_schema_to_ruby_default(default, type) click to toggle source

Convert the given default, which should be a database specific string, into a ruby object.

    # File lib/sequel/database/query.rb
260 def column_schema_to_ruby_default(default, type)
261   return default unless default.is_a?(String)
262   if COLUMN_SCHEMA_DATETIME_TYPES.include?(type)
263     if /now|today|CURRENT|getdate|\ADate\(\)\z/i.match(default)
264       if type == :date
265         return Sequel::CURRENT_DATE
266       else
267         return Sequel::CURRENT_TIMESTAMP
268       end
269     end
270   end
271   default = column_schema_normalize_default(default, type)
272   column_schema_default_to_ruby_value(default, type) rescue nil
273 end
input_identifier_meth(ds=nil) click to toggle source

Return a Method object for the dataset's output_identifier_method. Used in metadata parsing to make sure the returned information is in the correct format.

    # File lib/sequel/database/query.rb
286 def input_identifier_meth(ds=nil)
287   (ds || dataset).method(:input_identifier)
288 end
metadata_dataset() click to toggle source

Return a dataset that uses the default identifier input and output methods for this database. Used when parsing metadata so that column symbols are returned as expected.

    # File lib/sequel/database/query.rb
298 def metadata_dataset
299   @metadata_dataset ||= _metadata_dataset
300 end
output_identifier_meth(ds=nil) click to toggle source

Return a Method object for the dataset's output_identifier_method. Used in metadata parsing to make sure the returned information is in the correct format.

    # File lib/sequel/database/query.rb
305 def output_identifier_meth(ds=nil)
306   (ds || dataset).method(:output_identifier)
307 end
remove_cached_schema(table) click to toggle source

Remove the cached schema for the given schema name

    # File lib/sequel/database/query.rb
310 def remove_cached_schema(table)
311   cache = @default_dataset.send(:cache)
312   Sequel.synchronize{cache.clear}
313   k = quote_schema_table(table)
314   Sequel.synchronize{@schemas.delete(k)}
315 end
schema_column_type(db_type) click to toggle source

Match the database's column type to a ruby type via a regular expression, and return the ruby type as a symbol such as :integer or :string.

    # File lib/sequel/database/query.rb
320 def schema_column_type(db_type)
321   case db_type
322   when /\A(character( varying)?|n?(var)?char|n?text|string|clob)/io
323     :string
324   when /\A(int(eger)?|(big|small|tiny)int)/io
325     :integer
326   when /\Adate\z/io
327     :date
328   when /\A((small)?datetime|timestamp( with(out)? time zone)?)(\(\d+\))?\z/io
329     :datetime
330   when /\Atime( with(out)? time zone)?\z/io
331     :time
332   when /\A(bool(ean)?)\z/io
333     :boolean
334   when /\A(real|float|double( precision)?|double\(\d+,\d+\)( unsigned)?)\z/io
335     :float
336   when /\A(?:(?:(?:num(?:ber|eric)?|decimal)(?:\(\d+,\s*(\d+|false|true)\))?))\z/io
337     $1 && ['0', 'false'].include?($1) ? :integer : :decimal
338   when /bytea|blob|image|(var)?binary/io
339     :blob
340   when /\Aenum/io
341     :enum
342   end
343 end
schema_post_process(cols) click to toggle source

Post process the schema values.

    # File lib/sequel/database/query.rb
346 def schema_post_process(cols)
347   if RUBY_VERSION >= '2.5'
348     cols.each do |_, h|
349       db_type = h[:db_type]
350       if db_type.is_a?(String)
351         h[:db_type] = -db_type
352       end
353     end
354   end
355 
356   cols.each do |_,c|
357     c.each_value do |val|
358       val.freeze if val.is_a?(String)
359     end
360   end
361 end

2 - Methods that modify the database schema

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Constants

COLUMN_DEFINITION_ORDER

The order of column modifiers to use when defining a column.

COMBINABLE_ALTER_TABLE_OPS

The alter table operations that are combinable.

Public Instance Methods

add_column(table, *args) click to toggle source

Adds a column to the specified table. This method expects a column name, a datatype and optionally a hash with additional constraints and options:

DB.add_column :items, :name, String, unique: true, null: false
DB.add_column :items, :category, String, default: 'ruby'

See alter_table.

   # File lib/sequel/database/schema_methods.rb
25 def add_column(table, *args)
26   alter_table(table) {add_column(*args)}
27 end
add_index(table, columns, options=OPTS) click to toggle source

Adds an index to a table for the given columns:

DB.add_index :posts, :title
DB.add_index :posts, [:author, :title], unique: true

Options:

:ignore_errors

Ignore any DatabaseErrors that are raised

:name

Name to use for index instead of default

See alter_table.

   # File lib/sequel/database/schema_methods.rb
40 def add_index(table, columns, options=OPTS)
41   e = options[:ignore_errors]
42   begin
43     alter_table(table){add_index(columns, options)}
44   rescue DatabaseError
45     raise unless e
46   end
47   nil
48 end
alter_table(name, &block) click to toggle source

Alters the given table with the specified block. Example:

DB.alter_table :items do
  add_column :category, String, default: 'ruby'
  drop_column :category
  rename_column :cntr, :counter
  set_column_type :value, Float
  set_column_default :value, 4.2
  add_index [:group, :category]
  drop_index [:group, :category]
end

Note that add_column accepts all the options available for column definitions using create_table, and add_index accepts all the options available for index definition.

See Schema::AlterTableGenerator and the “Migrations and Schema Modification” guide.

   # File lib/sequel/database/schema_methods.rb
67 def alter_table(name, &block)
68   generator = alter_table_generator(&block)
69   remove_cached_schema(name)
70   apply_alter_table_generator(name, generator)
71   nil
72 end
alter_table_generator(&block) click to toggle source

Return a new Schema::AlterTableGenerator instance with the receiver as the database and the given block.

   # File lib/sequel/database/schema_methods.rb
76 def alter_table_generator(&block)
77   alter_table_generator_class.new(self, &block)
78 end
create_join_table(hash, options=OPTS) click to toggle source

Create a join table using a hash of foreign keys to referenced table names. Example:

create_join_table(cat_id: :cats, dog_id: :dogs)
# CREATE TABLE cats_dogs (
#  cat_id integer NOT NULL REFERENCES cats,
#  dog_id integer NOT NULL REFERENCES dogs,
#  PRIMARY KEY (cat_id, dog_id)
# )
# CREATE INDEX cats_dogs_dog_id_cat_id_index ON cats_dogs(dog_id, cat_id)

The primary key and index are used so that almost all operations on the table can benefit from one of the two indexes, and the primary key ensures that entries in the table are unique, which is the typical desire for a join table.

The default table name this will create is the sorted version of the two hash values, joined by an underscore. So the following two method calls create the same table:

create_join_table(cat_id: :cats, dog_id: :dogs) # cats_dogs
create_join_table(dog_id: :dogs, cat_id: :cats) # cats_dogs

You can provide column options by making the values in the hash be option hashes, so long as the option hashes have a :table entry giving the table referenced:

create_join_table(cat_id: {table: :cats, type: :Bignum}, dog_id: :dogs)

You can provide a second argument which is a table options hash:

create_join_table({cat_id: :cats, dog_id: :dogs}, temp: true)

Some table options are handled specially:

:index_options

The options to pass to the index

:name

The name of the table to create

:no_index

Set to true not to create the second index.

:no_primary_key

Set to true to not create the primary key.

    # File lib/sequel/database/schema_methods.rb
119 def create_join_table(hash, options=OPTS)
120   keys = hash.keys.sort
121   create_table(join_table_name(hash, options), options) do
122     keys.each do |key|
123       v = hash[key]
124       unless v.is_a?(Hash)
125         v = {:table=>v}
126       end
127       v[:null] = false unless v.has_key?(:null)
128       foreign_key(key, v)
129     end
130     primary_key(keys) unless options[:no_primary_key]
131     index(keys.reverse, options[:index_options] || OPTS) unless options[:no_index]
132   end
133   nil
134 end
create_join_table!(hash, options=OPTS) click to toggle source

Forcibly create a join table, attempting to drop it if it already exists, then creating it.

    # File lib/sequel/database/schema_methods.rb
137 def create_join_table!(hash, options=OPTS)
138   drop_table?(join_table_name(hash, options))
139   create_join_table(hash, options)
140 end
create_join_table?(hash, options=OPTS) click to toggle source

Creates the join table unless it already exists.

    # File lib/sequel/database/schema_methods.rb
143 def create_join_table?(hash, options=OPTS)
144   if supports_create_table_if_not_exists? && options[:no_index]
145     create_join_table(hash, options.merge(:if_not_exists=>true))
146   elsif !table_exists?(join_table_name(hash, options))
147     create_join_table(hash, options)
148   end
149 end
create_or_replace_view(name, source, options = OPTS) click to toggle source

Creates a view, replacing a view with the same name if one already exists.

DB.create_or_replace_view(:some_items, "SELECT * FROM items WHERE price < 100")
DB.create_or_replace_view(:some_items, DB[:items].where(category: 'ruby'))

For databases where replacing a view is not natively supported, support is emulated by dropping a view with the same name before creating the view.

    # File lib/sequel/database/schema_methods.rb
238 def create_or_replace_view(name, source, options = OPTS)
239   if supports_create_or_replace_view?
240     options = options.merge(:replace=>true)
241   else
242     drop_view(name) rescue nil
243   end
244 
245   create_view(name, source, options)
246   nil
247 end
create_table(name, options=OPTS, &block) click to toggle source

Creates a table with the columns given in the provided block:

DB.create_table :posts do
  primary_key :id
  column :title, String
  String :content
  index :title
end

General options:

:as

Create the table using the value, which should be either a dataset or a literal SQL string. If this option is used, a block should not be given to the method.

:ignore_index_errors

Ignore any errors when creating indexes.

:temp

Create the table as a temporary table.

MySQL specific options:

:charset

The character set to use for the table.

:collate

The collation to use for the table.

:engine

The table engine to use for the table.

PostgreSQL specific options:

:on_commit

Either :preserve_rows (default), :drop or :delete_rows. Should only be specified when creating a temporary table.

:foreign

Create a foreign table. The value should be the name of the foreign server that was specified in CREATE SERVER.

:inherits

Inherit from a different table. An array can be specified to inherit from multiple tables.

:unlogged

Create the table as an unlogged table.

:options

The OPTIONS clause to use for foreign tables. Should be a hash where keys are option names and values are option values. Note that option names are unquoted, so you should not use untrusted keys.

See Schema::CreateTableGenerator and the “Schema Modification” guide.

    # File lib/sequel/database/schema_methods.rb
186 def create_table(name, options=OPTS, &block)
187   remove_cached_schema(name)
188   if sql = options[:as]
189     raise(Error, "can't provide both :as option and block to create_table") if block
190     create_table_as(name, sql, options)
191   else
192     generator = options[:generator] || create_table_generator(&block)
193     create_table_from_generator(name, generator, options)
194     create_table_indexes_from_generator(name, generator, options)
195   end
196   nil
197 end
create_table!(name, options=OPTS, &block) click to toggle source

Forcibly create a table, attempting to drop it if it already exists, then creating it.

DB.create_table!(:a){Integer :a} 
# SELECT NULL FROM a LIMIT 1 -- check existence
# DROP TABLE a -- drop table if already exists
# CREATE TABLE a (a integer)
    # File lib/sequel/database/schema_methods.rb
205 def create_table!(name, options=OPTS, &block)
206   drop_table?(name)
207   create_table(name, options, &block)
208 end
create_table?(name, options=OPTS, &block) click to toggle source

Creates the table unless the table already exists.

DB.create_table?(:a){Integer :a} 
# SELECT NULL FROM a LIMIT 1 -- check existence
# CREATE TABLE a (a integer) -- if it doesn't already exist
    # File lib/sequel/database/schema_methods.rb
215 def create_table?(name, options=OPTS, &block)
216   options = options.dup
217   generator = options[:generator] ||= create_table_generator(&block)
218   if generator.indexes.empty? && supports_create_table_if_not_exists?
219     create_table(name, options.merge!(:if_not_exists=>true))
220   elsif !table_exists?(name)
221     create_table(name, options)
222   end
223 end
create_table_generator(&block) click to toggle source

Return a new Schema::CreateTableGenerator instance with the receiver as the database and the given block.

    # File lib/sequel/database/schema_methods.rb
227 def create_table_generator(&block)
228   create_table_generator_class.new(self, &block)
229 end
create_view(name, source, options = OPTS) click to toggle source

Creates a view based on a dataset or an SQL string:

DB.create_view(:cheap_items, "SELECT * FROM items WHERE price < 100")
# CREATE VIEW cheap_items AS
# SELECT * FROM items WHERE price < 100

DB.create_view(:ruby_items, DB[:items].where(category: 'ruby'))
# CREATE VIEW ruby_items AS
# SELECT * FROM items WHERE (category = 'ruby')

DB.create_view(:checked_items, DB[:items].where(:foo), check: true)
# CREATE VIEW checked_items AS
# SELECT * FROM items WHERE foo
# WITH CHECK OPTION

Options:

:columns

The column names to use for the view. If not given, automatically determined based on the input dataset.

:check

Adds a WITH CHECK OPTION clause, so that attempting to modify rows in the underlying table that would not be returned by the view is not allowed. This can be set to :local to use WITH LOCAL CHECK OPTION.

PostgreSQL/SQLite specific option:

:temp

Create a temporary view, automatically dropped on disconnect.

PostgreSQL specific options:

:materialized

Creates a materialized view, similar to a regular view, but backed by a physical table.

:recursive

Creates a recursive view. As columns must be specified for recursive views, you can also set them as the value of this option. Since a recursive view requires a union that isn't in a subquery, if you are providing a Dataset as the source argument, if should probably call the union method with the all: true and from_self: false options.

    # File lib/sequel/database/schema_methods.rb
284 def create_view(name, source, options = OPTS)
285   execute_ddl(create_view_sql(name, source, options))
286   remove_cached_schema(name)
287   nil
288 end
drop_column(table, *args) click to toggle source

Removes a column from the specified table:

DB.drop_column :items, :category

See alter_table.

    # File lib/sequel/database/schema_methods.rb
295 def drop_column(table, *args)
296   alter_table(table) {drop_column(*args)}
297 end
drop_index(table, columns, options=OPTS) click to toggle source

Removes an index for the given table and column(s):

DB.drop_index :posts, :title
DB.drop_index :posts, [:author, :title]

See alter_table.

    # File lib/sequel/database/schema_methods.rb
305 def drop_index(table, columns, options=OPTS)
306   alter_table(table){drop_index(columns, options)}
307 end
drop_join_table(hash, options=OPTS) click to toggle source

Drop the join table that would have been created with the same arguments to create_join_table:

drop_join_table(cat_id: :cats, dog_id: :dogs)
# DROP TABLE cats_dogs
    # File lib/sequel/database/schema_methods.rb
314 def drop_join_table(hash, options=OPTS)
315   drop_table(join_table_name(hash, options), options)
316 end
drop_table(*names) click to toggle source

Drops one or more tables corresponding to the given names:

DB.drop_table(:posts) # DROP TABLE posts
DB.drop_table(:posts, :comments)
DB.drop_table(:posts, :comments, cascade: true)
    # File lib/sequel/database/schema_methods.rb
323 def drop_table(*names)
324   options = names.last.is_a?(Hash) ? names.pop : OPTS 
325   names.each do |n|
326     execute_ddl(drop_table_sql(n, options))
327     remove_cached_schema(n)
328   end
329   nil
330 end
drop_table?(*names) click to toggle source

Drops the table if it already exists. If it doesn't exist, does nothing.

DB.drop_table?(:a)
# SELECT NULL FROM a LIMIT 1 -- check existence
# DROP TABLE a -- if it already exists
    # File lib/sequel/database/schema_methods.rb
338 def drop_table?(*names)
339   options = names.last.is_a?(Hash) ? names.pop : OPTS
340   if supports_drop_table_if_exists?
341     options = options.merge(:if_exists=>true)
342     names.each do |name|
343       drop_table(name, options)
344     end
345   else
346     names.each do |name|
347       drop_table(name, options) if table_exists?(name)
348     end
349   end
350   nil
351 end
drop_view(*names) click to toggle source

Drops one or more views corresponding to the given names:

DB.drop_view(:cheap_items)
DB.drop_view(:cheap_items, :pricey_items)
DB.drop_view(:cheap_items, :pricey_items, cascade: true)
DB.drop_view(:cheap_items, :pricey_items, if_exists: true)

Options:

:cascade

Also drop objects depending on this view.

:if_exists

Do not raise an error if the view does not exist.

PostgreSQL specific options:

:materialized

Drop a materialized view.

    # File lib/sequel/database/schema_methods.rb
366 def drop_view(*names)
367   options = names.last.is_a?(Hash) ? names.pop : OPTS
368   names.each do |n|
369     execute_ddl(drop_view_sql(n, options))
370     remove_cached_schema(n)
371   end
372   nil
373 end
rename_column(table, *args) click to toggle source

Renames a column in the specified table. This method expects the current column name and the new column name:

DB.rename_column :items, :cntr, :counter

See alter_table.

    # File lib/sequel/database/schema_methods.rb
392 def rename_column(table, *args)
393   alter_table(table) {rename_column(*args)}
394 end
rename_table(name, new_name) click to toggle source

Renames a table:

DB.tables #=> [:items]
DB.rename_table :items, :old_items
DB.tables #=> [:old_items]
    # File lib/sequel/database/schema_methods.rb
380 def rename_table(name, new_name)
381   execute_ddl(rename_table_sql(name, new_name))
382   remove_cached_schema(name)
383   nil
384 end
set_column_default(table, *args) click to toggle source

Sets the default value for the given column in the given table:

DB.set_column_default :items, :category, 'perl!'

See alter_table.

    # File lib/sequel/database/schema_methods.rb
401 def set_column_default(table, *args)
402   alter_table(table) {set_column_default(*args)}
403 end
set_column_type(table, *args) click to toggle source

Set the data type for the given column in the given table:

DB.set_column_type :items, :price, :float

See alter_table.

    # File lib/sequel/database/schema_methods.rb
410 def set_column_type(table, *args)
411   alter_table(table) {set_column_type(*args)}
412 end

Private Instance Methods

alter_table_add_column_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
450 def alter_table_add_column_sql(table, op)
451   "ADD COLUMN #{column_definition_sql(op)}"
452 end
alter_table_add_constraint_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
474 def alter_table_add_constraint_sql(table, op)
475   "ADD #{constraint_definition_sql(op)}"
476 end
alter_table_drop_column_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
454 def alter_table_drop_column_sql(table, op)
455   "DROP COLUMN #{quote_identifier(op[:name])}#{' CASCADE' if op[:cascade]}"
456 end
alter_table_drop_constraint_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
478 def alter_table_drop_constraint_sql(table, op)
479   quoted_name = quote_identifier(op[:name]) if op[:name]
480   if op[:type] == :foreign_key
481     quoted_name ||= quote_identifier(foreign_key_name(table, op[:columns]))
482   end
483   "DROP CONSTRAINT #{quoted_name}#{' CASCADE' if op[:cascade]}"
484 end
alter_table_generator_class() click to toggle source

The class used for alter_table generators.

    # File lib/sequel/database/schema_methods.rb
435 def alter_table_generator_class
436   Schema::AlterTableGenerator
437 end
alter_table_op_sql(table, op) click to toggle source

SQL fragment for given alter table operation.

    # File lib/sequel/database/schema_methods.rb
440 def alter_table_op_sql(table, op)
441   meth = "alter_table_#{op[:op]}_sql"
442   if respond_to?(meth, true)
443     # Allow calling private methods as alter table op sql methods are private
444     send(meth, table, op)
445   else
446     raise Error, "Unsupported ALTER TABLE operation: #{op[:op]}"
447   end
448 end
alter_table_rename_column_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
458 def alter_table_rename_column_sql(table, op)
459   "RENAME COLUMN #{quote_identifier(op[:name])} TO #{quote_identifier(op[:new_name])}"
460 end
alter_table_set_column_default_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
466 def alter_table_set_column_default_sql(table, op)
467   "ALTER COLUMN #{quote_identifier(op[:name])} SET DEFAULT #{literal(op[:default])}"
468 end
alter_table_set_column_null_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
470 def alter_table_set_column_null_sql(table, op)
471   "ALTER COLUMN #{quote_identifier(op[:name])} #{op[:null] ? 'DROP' : 'SET'} NOT NULL"
472 end
alter_table_set_column_type_sql(table, op) click to toggle source
    # File lib/sequel/database/schema_methods.rb
462 def alter_table_set_column_type_sql(table, op)
463   "ALTER COLUMN #{quote_identifier(op[:name])} TYPE #{type_literal(op)}"
464 end
alter_table_sql(table, op) click to toggle source

The SQL to execute to modify the table. op should be one of the operations returned by the AlterTableGenerator.

    # File lib/sequel/database/schema_methods.rb
488 def alter_table_sql(table, op)
489   case op[:op]
490   when :add_index
491     index_definition_sql(table, op)
492   when :drop_index
493     drop_index_sql(table, op)
494   else
495     "ALTER TABLE #{quote_schema_table(table)} #{alter_table_op_sql(table, op)}"
496   end
497 end
alter_table_sql_list(table, operations) click to toggle source

Array of SQL statements used to modify the table, corresponding to changes specified by the operations.

    # File lib/sequel/database/schema_methods.rb
501 def alter_table_sql_list(table, operations)
502   if supports_combining_alter_table_ops?
503     grouped_ops = []
504     last_combinable = false
505     operations.each do |op|
506       if combinable_alter_table_op?(op)
507         if sql = alter_table_op_sql(table, op)
508           grouped_ops << [] unless last_combinable
509           grouped_ops.last << sql
510           last_combinable = true
511         end
512       elsif sql = alter_table_sql(table, op)
513         Array(sql).each{|s| grouped_ops << s}
514         last_combinable = false
515       end
516     end
517     grouped_ops.map do |gop|
518       if gop.is_a?(Array)
519         "ALTER TABLE #{quote_schema_table(table)} #{gop.join(', ')}"
520       else
521         gop
522       end
523     end
524   else
525     operations.map{|op| alter_table_sql(table, op)}.flatten.compact
526   end
527 end
apply_alter_table(name, ops) click to toggle source

Apply the changes in the given alter table ops to the table given by name.

    # File lib/sequel/database/schema_methods.rb
417 def apply_alter_table(name, ops)
418   alter_table_sql_list(name, ops).each{|sql| execute_ddl(sql)}
419 end
apply_alter_table_generator(name, generator) click to toggle source

Apply the operations in the given generator to the table given by name.

    # File lib/sequel/database/schema_methods.rb
422 def apply_alter_table_generator(name, generator)
423   ops = generator.operations
424 
425   unless can_add_primary_key_constraint_on_nullable_columns?
426     if add_pk = ops.find{|op| op[:op] == :add_constraint && op[:type] == :primary_key}
427       ops = add_pk[:columns].map{|column| {:op => :set_column_null, :name => column, :null => false}} + ops
428     end
429   end
430 
431   apply_alter_table(name, ops)
432 end
auto_increment_sql() click to toggle source

The SQL string specify the autoincrement property, generally used by primary keys.

    # File lib/sequel/database/schema_methods.rb
531 def auto_increment_sql
532   'AUTOINCREMENT'
533 end
column_definition_auto_increment_sql(sql, column) click to toggle source

Add auto increment SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
549 def column_definition_auto_increment_sql(sql, column)
550   sql << " #{auto_increment_sql}" if column[:auto_increment]
551 end
column_definition_collate_sql(sql, column) click to toggle source

Add collate SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
554 def column_definition_collate_sql(sql, column)
555   if collate = column[:collate]
556     sql << " COLLATE #{collate}"
557   end
558 end
column_definition_default_sql(sql, column) click to toggle source

Add default SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
561 def column_definition_default_sql(sql, column)
562   sql << " DEFAULT #{literal(column[:default])}" if column.include?(:default)
563 end
column_definition_null_sql(sql, column) click to toggle source

Add null/not null SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
566 def column_definition_null_sql(sql, column)
567   null = column.fetch(:null, column[:allow_null])
568   if null.nil? && !can_add_primary_key_constraint_on_nullable_columns? && column[:primary_key]
569     null = false
570   end
571 
572   case null
573   when false
574     sql << ' NOT NULL'
575   when true
576     sql << ' NULL'
577   end
578 end
column_definition_order() click to toggle source

The order of the column definition, as an array of symbols.

    # File lib/sequel/database/schema_methods.rb
536 def column_definition_order
537   COLUMN_DEFINITION_ORDER
538 end
column_definition_primary_key_sql(sql, column) click to toggle source

Add primary key SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
581 def column_definition_primary_key_sql(sql, column)
582   if column[:primary_key]
583     if name = column[:primary_key_constraint_name]
584       sql << " CONSTRAINT #{quote_identifier(name)}"
585     end
586     sql << ' PRIMARY KEY'
587   end
588 end
column_definition_references_sql(sql, column) click to toggle source

Add foreign key reference SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
591 def column_definition_references_sql(sql, column)
592   if column[:table]
593     if name = column[:foreign_key_constraint_name]
594      sql << " CONSTRAINT #{quote_identifier(name)}"
595     end
596     sql << column_references_column_constraint_sql(column)
597   end
598 end
column_definition_sql(column) click to toggle source

SQL fragment containing the column creation SQL for the given column.

    # File lib/sequel/database/schema_methods.rb
541 def column_definition_sql(column)
542   sql = String.new
543   sql << "#{quote_identifier(column[:name])} #{type_literal(column)}"
544   column_definition_order.each{|m| send(:"column_definition_#{m}_sql", sql, column)}
545   sql
546 end
column_definition_unique_sql(sql, column) click to toggle source

Add unique constraint SQL fragment to column creation SQL.

    # File lib/sequel/database/schema_methods.rb
601 def column_definition_unique_sql(sql, column)
602   if column[:unique]
603     if name = column[:unique_constraint_name]
604       sql << " CONSTRAINT #{quote_identifier(name)}"
605     end
606     sql << ' UNIQUE'
607   end
608 end
column_list_sql(generator) click to toggle source

SQL for all given columns, used inside a CREATE TABLE block.

    # File lib/sequel/database/schema_methods.rb
611 def column_list_sql(generator)
612   (generator.columns.map{|c| column_definition_sql(c)} + generator.constraints.map{|c| constraint_definition_sql(c)}).join(', ')
613 end
column_references_column_constraint_sql(column) click to toggle source

SQL fragment for column foreign key references (column constraints)

    # File lib/sequel/database/schema_methods.rb
616 def column_references_column_constraint_sql(column)
617   column_references_sql(column)
618 end
column_references_sql(column) click to toggle source

SQL fragment for column foreign key references

    # File lib/sequel/database/schema_methods.rb
621 def column_references_sql(column)
622   sql = String.new
623   sql << " REFERENCES #{quote_schema_table(column[:table])}"
624   sql << "(#{Array(column[:key]).map{|x| quote_identifier(x)}.join(', ')})" if column[:key]
625   sql << " ON DELETE #{on_delete_clause(column[:on_delete])}" if column[:on_delete]
626   sql << " ON UPDATE #{on_update_clause(column[:on_update])}" if column[:on_update]
627   constraint_deferrable_sql_append(sql, column[:deferrable])
628   sql
629 end
column_references_table_constraint_sql(constraint) click to toggle source

SQL fragment for table foreign key references (table constraints)

    # File lib/sequel/database/schema_methods.rb
632 def column_references_table_constraint_sql(constraint)
633   "FOREIGN KEY #{literal(constraint[:columns])}#{column_references_sql(constraint)}"
634 end
combinable_alter_table_op?(op) click to toggle source

Whether the given alter table operation is combinable.

    # File lib/sequel/database/schema_methods.rb
637 def combinable_alter_table_op?(op)
638   COMBINABLE_ALTER_TABLE_OPS.include?(op[:op])
639 end
constraint_deferrable_sql_append(sql, defer) click to toggle source

SQL fragment specifying the deferrable constraint attributes.

    # File lib/sequel/database/schema_methods.rb
666 def constraint_deferrable_sql_append(sql, defer)
667   case defer
668   when nil
669   when false
670     sql << ' NOT DEFERRABLE'
671   when :immediate
672     sql << ' DEFERRABLE INITIALLY IMMEDIATE'
673   else
674     sql << ' DEFERRABLE INITIALLY DEFERRED'
675   end
676 end
constraint_definition_sql(constraint) click to toggle source

SQL fragment specifying a constraint on a table.

    # File lib/sequel/database/schema_methods.rb
642 def constraint_definition_sql(constraint)
643   sql = String.new
644   sql << "CONSTRAINT #{quote_identifier(constraint[:name])} " if constraint[:name] 
645   case constraint[:type]
646   when :check
647     check = constraint[:check]
648     check = check.first if check.is_a?(Array) && check.length == 1
649     check = filter_expr(check)
650     check = "(#{check})" unless check[0..0] == '(' && check[-1..-1] == ')'
651     sql << "CHECK #{check}"
652   when :primary_key
653     sql << "PRIMARY KEY #{literal(constraint[:columns])}"
654   when :foreign_key
655     sql << column_references_table_constraint_sql(constraint.merge(:deferrable=>nil))
656   when :unique
657     sql << "UNIQUE #{literal(constraint[:columns])}"
658   else
659     raise Error, "Invalid constraint type #{constraint[:type]}, should be :check, :primary_key, :foreign_key, or :unique"
660   end
661   constraint_deferrable_sql_append(sql, constraint[:deferrable])
662   sql
663 end
create_table_as(name, sql, options) click to toggle source

Run SQL statement to create the table with the given name from the given SELECT sql statement.

    # File lib/sequel/database/schema_methods.rb
736 def create_table_as(name, sql, options)
737   sql = sql.sql if sql.is_a?(Sequel::Dataset)
738   run(create_table_as_sql(name, sql, options))
739 end
create_table_as_sql(name, sql, options) click to toggle source

SQL statement for creating a table from the result of a SELECT statement. sql should be a string representing a SELECT query.

    # File lib/sequel/database/schema_methods.rb
743 def create_table_as_sql(name, sql, options)
744   "#{create_table_prefix_sql(name, options)} AS #{sql}"
745 end
create_table_from_generator(name, generator, options) click to toggle source

Execute the create table statements using the generator.

    # File lib/sequel/database/schema_methods.rb
679 def create_table_from_generator(name, generator, options)
680   execute_ddl(create_table_sql(name, generator, options))
681 end
create_table_generator_class() click to toggle source

The class used for create_table generators.

    # File lib/sequel/database/schema_methods.rb
684 def create_table_generator_class
685   Schema::CreateTableGenerator
686 end
create_table_indexes_from_generator(name, generator, options) click to toggle source

Execute the create index statements using the generator.

    # File lib/sequel/database/schema_methods.rb
689 def create_table_indexes_from_generator(name, generator, options)
690   e = options[:ignore_index_errors] || options[:if_not_exists]
691   generator.indexes.each do |index|
692     begin
693       pr = proc{index_sql_list(name, [index]).each{|sql| execute_ddl(sql)}}
694       supports_transactional_ddl? ? transaction(:savepoint=>:only, &pr) : pr.call
695     rescue Error
696       raise unless e
697     end
698   end
699 end
create_table_prefix_sql(name, options) click to toggle source

SQL fragment for initial part of CREATE TABLE statement

    # File lib/sequel/database/schema_methods.rb
748 def create_table_prefix_sql(name, options)
749   "CREATE #{temporary_table_sql if options[:temp]}TABLE#{' IF NOT EXISTS' if options[:if_not_exists]} #{options[:temp] ? quote_identifier(name) : quote_schema_table(name)}"
750 end
create_table_sql(name, generator, options) click to toggle source

SQL statement for creating a table with the given name, columns, and options

    # File lib/sequel/database/schema_methods.rb
702 def create_table_sql(name, generator, options)
703   unless supports_named_column_constraints?
704     # Split column constraints into table constraints if they have a name
705     generator.columns.each do |c|
706       if (constraint_name = c.delete(:foreign_key_constraint_name)) && (table = c.delete(:table))
707         opts = {}
708         opts[:name] = constraint_name
709         [:key, :on_delete, :on_update, :deferrable].each{|k| opts[k] = c[k]}
710         generator.foreign_key([c[:name]], table, opts)
711       end
712       if (constraint_name = c.delete(:unique_constraint_name)) && c.delete(:unique)
713         generator.unique(c[:name], :name=>constraint_name)
714       end
715       if (constraint_name = c.delete(:primary_key_constraint_name)) && c.delete(:primary_key)
716         generator.primary_key([c[:name]], :name=>constraint_name)
717       end
718     end
719   end
720 
721   unless can_add_primary_key_constraint_on_nullable_columns?
722     if pk = generator.constraints.find{|op| op[:type] == :primary_key}
723       pk[:columns].each do |column|
724         if matched_column = generator.columns.find{|gc| gc[:name] == column}
725           matched_column[:null] = false
726         end
727       end
728     end
729   end
730 
731   "#{create_table_prefix_sql(name, options)} (#{column_list_sql(generator)})"
732 end
create_view_prefix_sql(name, options) click to toggle source

SQL fragment for initial part of CREATE VIEW statement

    # File lib/sequel/database/schema_methods.rb
753 def create_view_prefix_sql(name, options)
754   create_view_sql_append_columns("CREATE #{'OR REPLACE 'if options[:replace]}VIEW #{quote_schema_table(name)}", options[:columns])
755 end
create_view_sql(name, source, options) click to toggle source

SQL statement for creating a view.

    # File lib/sequel/database/schema_methods.rb
758 def create_view_sql(name, source, options)
759   source = source.sql if source.is_a?(Dataset)
760   sql = String.new
761   sql << "#{create_view_prefix_sql(name, options)} AS #{source}"
762   if check = options[:check]
763     sql << " WITH#{' LOCAL' if check == :local} CHECK OPTION"
764   end
765   sql
766 end
create_view_sql_append_columns(sql, columns) click to toggle source

Append the column list to the SQL, if a column list is given.

    # File lib/sequel/database/schema_methods.rb
769 def create_view_sql_append_columns(sql, columns)
770   if columns
771     sql += ' ('
772     schema_utility_dataset.send(:identifier_list_append, sql, columns)
773     sql << ')'
774   end
775   sql
776 end
default_index_name(table_name, columns) click to toggle source

Default index name for the table and columns, may be too long for certain databases.

    # File lib/sequel/database/schema_methods.rb
780 def default_index_name(table_name, columns)
781   schema, table = schema_and_table(table_name)
782   "#{"#{schema}_" if schema}#{table}_#{columns.map{|c| [String, Symbol].any?{|cl| c.is_a?(cl)} ? c : literal(c).gsub(/\W/, '_')}.join('_')}_index"
783 end
drop_index_sql(table, op) click to toggle source

The SQL to drop an index for the table.

    # File lib/sequel/database/schema_methods.rb
793 def drop_index_sql(table, op)
794   "DROP INDEX #{quote_identifier(op[:name] || default_index_name(table, op[:columns]))}"
795 end
drop_table_sql(name, options) click to toggle source

SQL DDL statement to drop the table with the given name.

    # File lib/sequel/database/schema_methods.rb
798 def drop_table_sql(name, options)
799   "DROP TABLE#{' IF EXISTS' if options[:if_exists]} #{quote_schema_table(name)}#{' CASCADE' if options[:cascade]}"
800 end
drop_view_sql(name, options) click to toggle source

SQL DDL statement to drop a view with the given name.

    # File lib/sequel/database/schema_methods.rb
803 def drop_view_sql(name, options)
804   "DROP VIEW#{' IF EXISTS' if options[:if_exists]} #{quote_schema_table(name)}#{' CASCADE' if options[:cascade]}"
805 end
filter_expr(*args, &block) click to toggle source

Proxy the filter_expr call to the dataset, used for creating constraints. Support passing Proc arguments as blocks, as well as treating plain strings as literal strings, so that previous migrations that used this API do not break.

    # File lib/sequel/database/schema_methods.rb
810 def filter_expr(*args, &block)
811   if args.length == 1
812     arg = args.first
813     if arg.is_a?(Proc) && !block
814       block = args.first
815       args = nil
816     elsif arg.is_a?(String)
817       args = [Sequel.lit(*args)]
818     elsif arg.is_a?(Array)
819       if arg.first.is_a?(String)
820         args = [Sequel.lit(*arg)]
821       elsif arg.length > 1
822         args = [Sequel.&(*arg)]
823       end
824     end
825   end
826   schema_utility_dataset.literal(schema_utility_dataset.send(:filter_expr, *args, &block))
827 end
foreign_key_name(table_name, columns) click to toggle source

Get foreign key name for given table and columns.

    # File lib/sequel/database/schema_methods.rb
786 def foreign_key_name(table_name, columns)
787   keys = foreign_key_list(table_name).select{|key| key[:columns] == columns}
788   raise(Error, "#{keys.empty? ? 'Missing' : 'Ambiguous'} foreign key for #{columns.inspect}") unless keys.size == 1
789   keys.first[:name]
790 end
index_definition_sql(table_name, index) click to toggle source

SQL statement for creating an index for the table with the given name and index specifications.

    # File lib/sequel/database/schema_methods.rb
831 def index_definition_sql(table_name, index)
832   index_name = index[:name] || default_index_name(table_name, index[:columns])
833   raise Error, "Index types are not supported for this database" if index[:type]
834   raise Error, "Partial indexes are not supported for this database" if index[:where] && !supports_partial_indexes?
835   "CREATE #{'UNIQUE ' if index[:unique]}INDEX #{quote_identifier(index_name)} ON #{quote_schema_table(table_name)} #{literal(index[:columns])}#{" WHERE #{filter_expr(index[:where])}" if index[:where]}"
836 end
index_sql_list(table_name, indexes) click to toggle source

Array of SQL statements, one for each index specification, for the given table.

    # File lib/sequel/database/schema_methods.rb
840 def index_sql_list(table_name, indexes)
841   indexes.map{|i| index_definition_sql(table_name, i)}
842 end
join_table_name(hash, options) click to toggle source

Extract the join table name from the arguments given to create_join_table. Also does argument validation for the create_join_table method.

    # File lib/sequel/database/schema_methods.rb
846 def join_table_name(hash, options)
847   entries = hash.values
848   raise Error, "must have 2 entries in hash given to (create|drop)_join_table" unless entries.length == 2
849   if options[:name]
850     options[:name]
851   else
852     table_names = entries.map{|e| join_table_name_extract(e)}
853     table_names.map(&:to_s).sort.join('_')
854   end
855 end
join_table_name_extract(entry) click to toggle source

Extract an individual join table name, which should either be a string or symbol, or a hash containing one of those as the value for :table.

    # File lib/sequel/database/schema_methods.rb
859 def join_table_name_extract(entry)
860   case entry
861   when Symbol, String
862     entry
863   when Hash
864     join_table_name_extract(entry[:table])
865   else
866     raise Error, "can't extract table name from #{entry.inspect}"
867   end
868 end
on_delete_clause(action) click to toggle source

SQL fragment to use for ON DELETE, based on the given action. The following actions are recognized:

:cascade

Delete rows referencing this row.

:no_action

Raise an error if other rows reference this row, allow deferring of the integrity check. This is the default.

:restrict

Raise an error if other rows reference this row, but do not allow deferring the integrity check.

:set_default

Set columns referencing this row to their default value.

:set_null

Set columns referencing this row to NULL.

Any other object given is just converted to a string, with “_” converted to “ ” and upcased.

    # File lib/sequel/database/schema_methods.rb
883 def on_delete_clause(action)
884   action.to_s.gsub("_", " ").upcase
885 end
on_update_clause(action) click to toggle source

Alias of on_delete_clause, since the two usually behave the same.

    # File lib/sequel/database/schema_methods.rb
888 def on_update_clause(action)
889   on_delete_clause(action)
890 end
quote_schema_table(table) click to toggle source

Proxy the quote_schema_table method to the dataset

    # File lib/sequel/database/schema_methods.rb
893 def quote_schema_table(table)
894   schema_utility_dataset.quote_schema_table(table)
895 end
rename_table_sql(name, new_name) click to toggle source

SQL statement for renaming a table.

    # File lib/sequel/database/schema_methods.rb
898 def rename_table_sql(name, new_name)
899   "ALTER TABLE #{quote_schema_table(name)} RENAME TO #{quote_schema_table(new_name)}"
900 end
schema_and_table(table_name) click to toggle source

Split the schema information from the table

    # File lib/sequel/database/schema_methods.rb
903 def schema_and_table(table_name)
904   schema_utility_dataset.schema_and_table(table_name)
905 end
schema_autoincrementing_primary_key?(schema) click to toggle source

Return true if the given column schema represents an autoincrementing primary key.

    # File lib/sequel/database/schema_methods.rb
908 def schema_autoincrementing_primary_key?(schema)
909   !!(schema[:primary_key] && schema[:auto_increment])
910 end
schema_utility_dataset() click to toggle source

The dataset to use for proxying certain schema methods.

    # File lib/sequel/database/schema_methods.rb
913 def schema_utility_dataset
914   @default_dataset
915 end
split_qualifiers(table_name) click to toggle source

Split the schema information from the table

    # File lib/sequel/database/schema_methods.rb
918 def split_qualifiers(table_name)
919   schema_utility_dataset.split_qualifiers(table_name)
920 end
temporary_table_sql() click to toggle source

SQL fragment for temporary table

    # File lib/sequel/database/schema_methods.rb
923 def temporary_table_sql
924   'TEMPORARY '
925 end
type_literal(column) click to toggle source

SQL fragment specifying the type of a given column.

    # File lib/sequel/database/schema_methods.rb
928 def type_literal(column)
929   case column[:type]
930   when Class
931     type_literal_generic(column)
932   when :Bignum
933     type_literal_generic_bignum_symbol(column)
934   else
935     type_literal_specific(column)
936   end
937 end
type_literal_generic(column) click to toggle source

SQL fragment specifying the full type of a column, consider the type with possible modifiers.

    # File lib/sequel/database/schema_methods.rb
941 def type_literal_generic(column)
942   meth = "type_literal_generic_#{column[:type].name.to_s.downcase}"
943   if respond_to?(meth, true)
944     # Allow calling private methods as per type literal generic methods are private
945     send(meth, column)
946   else
947     raise Error, "Unsupported ruby class used as database type: #{column[:type]}"
948   end
949 end
type_literal_generic_bigdecimal(column) click to toggle source

Alias for type_literal_generic_numeric, to make overriding in a subclass easier.

    # File lib/sequel/database/schema_methods.rb
952 def type_literal_generic_bigdecimal(column)
953   type_literal_generic_numeric(column)
954 end
type_literal_generic_bignum_symbol(column) click to toggle source

Sequel uses the bigint type by default for :Bignum symbol.

    # File lib/sequel/database/schema_methods.rb
957 def type_literal_generic_bignum_symbol(column)
958   :bigint
959 end
type_literal_generic_date(column) click to toggle source

Sequel uses the date type by default for Dates.

    # File lib/sequel/database/schema_methods.rb
962 def type_literal_generic_date(column)
963   :date
964 end
type_literal_generic_datetime(column) click to toggle source

Sequel uses the timestamp type by default for DateTimes.

    # File lib/sequel/database/schema_methods.rb
967 def type_literal_generic_datetime(column)
968   :timestamp
969 end
type_literal_generic_falseclass(column) click to toggle source

Alias for type_literal_generic_trueclass, to make overriding in a subclass easier.

    # File lib/sequel/database/schema_methods.rb
972 def type_literal_generic_falseclass(column)
973   type_literal_generic_trueclass(column)
974 end
type_literal_generic_file(column) click to toggle source

Sequel uses the blob type by default for Files.

    # File lib/sequel/database/schema_methods.rb
977 def type_literal_generic_file(column)
978   :blob
979 end
type_literal_generic_fixnum(column) click to toggle source

Alias for type_literal_generic_integer, to make overriding in a subclass easier.

    # File lib/sequel/database/schema_methods.rb
982 def type_literal_generic_fixnum(column)
983   type_literal_generic_integer(column)
984 end
type_literal_generic_float(column) click to toggle source

Sequel uses the double precision type by default for Floats.

    # File lib/sequel/database/schema_methods.rb
987 def type_literal_generic_float(column)
988   :"double precision"
989 end
type_literal_generic_integer(column) click to toggle source

Sequel uses the integer type by default for integers

    # File lib/sequel/database/schema_methods.rb
992 def type_literal_generic_integer(column)
993   :integer
994 end
type_literal_generic_numeric(column) click to toggle source

Sequel uses the numeric type by default for Numerics and BigDecimals. If a size is given, it is used, otherwise, it will default to whatever the database default is for an unsized value.

     # File lib/sequel/database/schema_methods.rb
 999 def type_literal_generic_numeric(column)
1000   column[:size] ? "numeric(#{Array(column[:size]).join(', ')})" : :numeric
1001 end
type_literal_generic_only_time(column) click to toggle source

Use time by default for Time values if :only_time option is used.

     # File lib/sequel/database/schema_methods.rb
1028 def type_literal_generic_only_time(column)
1029   :time
1030 end
type_literal_generic_string(column) click to toggle source

Sequel uses the varchar type by default for Strings. If a size isn't present, Sequel assumes a size of 255. If the :fixed option is used, Sequel uses the char type. If the :text option is used, Sequel uses the :text type.

     # File lib/sequel/database/schema_methods.rb
1007 def type_literal_generic_string(column)
1008   if column[:text]
1009     uses_clob_for_text? ? :clob : :text
1010   elsif column[:fixed]
1011     "char(#{column[:size]||default_string_column_size})"
1012   else
1013     "varchar(#{column[:size]||default_string_column_size})"
1014   end
1015 end
type_literal_generic_time(column) click to toggle source

Sequel uses the timestamp type by default for Time values. If the :only_time option is used, the time type is used.

     # File lib/sequel/database/schema_methods.rb
1019 def type_literal_generic_time(column)
1020   if column[:only_time]
1021     type_literal_generic_only_time(column)
1022   else
1023     type_literal_generic_datetime(column)
1024   end
1025 end
type_literal_generic_trueclass(column) click to toggle source

Sequel uses the boolean type by default for TrueClass and FalseClass.

     # File lib/sequel/database/schema_methods.rb
1033 def type_literal_generic_trueclass(column)
1034   :boolean
1035 end
type_literal_specific(column) click to toggle source

SQL fragment for the given type of a column if the column is not one of the generic types specified with a ruby class.

     # File lib/sequel/database/schema_methods.rb
1039 def type_literal_specific(column)
1040   type = column[:type]
1041   type = "double precision" if type.to_s == 'double'
1042   column[:size] ||= default_string_column_size if type.to_s == 'varchar'
1043   elements = column[:size] || column[:elements]
1044   "#{type}#{literal(Array(elements)) if elements}#{' UNSIGNED' if column[:unsigned]}"
1045 end
uses_clob_for_text?() click to toggle source

Whether clob should be used for String text: true columns.

     # File lib/sequel/database/schema_methods.rb
1048 def uses_clob_for_text?
1049   false
1050 end

3 - Methods that create datasets

↑ top

Public Instance Methods

[](*args) click to toggle source

Returns a dataset for the database. If the first argument is a string, the method acts as an alias for Database#fetch, returning a dataset for arbitrary SQL, with or without placeholders:

DB['SELECT * FROM items'].all
DB['SELECT * FROM items WHERE name = ?', my_name].all

Otherwise, acts as an alias for Database#from, setting the primary table for the dataset:

DB[:items].sql #=> "SELECT * FROM items"
   # File lib/sequel/database/dataset.rb
21 def [](*args)
22   args.first.is_a?(String) ? fetch(*args) : from(*args)
23 end
dataset() click to toggle source

Returns a blank dataset for this database.

DB.dataset # SELECT *
DB.dataset.from(:items) # SELECT * FROM items
   # File lib/sequel/database/dataset.rb
29 def dataset
30   @dataset_class.new(self)
31 end
fetch(sql, *args, &block) click to toggle source

Fetches records for an arbitrary SQL statement. If a block is given, it is used to iterate over the records:

DB.fetch('SELECT * FROM items'){|r| p r}

The fetch method returns a dataset instance:

DB.fetch('SELECT * FROM items').all

fetch can also perform parameterized queries for protection against SQL injection:

DB.fetch('SELECT * FROM items WHERE name = ?', my_name).all

See caveats listed in Dataset#with_sql regarding datasets using custom SQL and the methods that can be called on them.

   # File lib/sequel/database/dataset.rb
49 def fetch(sql, *args, &block)
50   ds = @default_dataset.with_sql(sql, *args)
51   ds.each(&block) if block
52   ds
53 end
from(*args, &block) click to toggle source

Returns a new dataset with the from method invoked. If a block is given, it acts as a virtual row block

DB.from(:items) # SELECT * FROM items
DB.from{schema[:table]} # SELECT * FROM schema.table
   # File lib/sequel/database/dataset.rb
60 def from(*args, &block)
61   if block
62     @default_dataset.from(*args, &block)
63   elsif args.length == 1 && (table = args[0]).is_a?(Symbol)
64     @default_dataset.send(:cached_dataset, :"_from_#{table}_ds"){@default_dataset.from(table)}
65   else
66     @default_dataset.from(*args)
67   end
68 end
select(*args, &block) click to toggle source

Returns a new dataset with the select method invoked.

DB.select(1) # SELECT 1
DB.select{server_version.function} # SELECT server_version()
DB.select(:id).from(:items) # SELECT id FROM items
   # File lib/sequel/database/dataset.rb
75 def select(*args, &block)
76   @default_dataset.select(*args, &block)
77 end

4 - Methods relating to adapters, connecting, disconnecting, and sharding

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Constants

ADAPTERS

Array of supported database adapters

Attributes

pool[R]

The connection pool for this Database instance. All Database instances have their own connection pools.

Public Class Methods

adapter_class(scheme) click to toggle source

The Database subclass for the given adapter scheme. Raises Sequel::AdapterNotFound if the adapter could not be loaded.

   # File lib/sequel/database/connecting.rb
16 def self.adapter_class(scheme)
17   scheme.is_a?(Class) ? scheme : load_adapter(scheme.to_sym)
18 end
adapter_scheme() click to toggle source

Returns the scheme symbol for the Database class.

   # File lib/sequel/database/connecting.rb
21 def self.adapter_scheme
22   @scheme
23 end
connect(conn_string, opts = OPTS) { |db| ... } click to toggle source

Connects to a database. See Sequel.connect.

   # File lib/sequel/database/connecting.rb
26 def self.connect(conn_string, opts = OPTS)
27   case conn_string
28   when String
29     if conn_string.start_with?('jdbc:')
30       c = adapter_class(:jdbc)
31       opts = opts.merge(:orig_opts=>opts.dup)
32       opts = {:uri=>conn_string}.merge!(opts)
33     else
34       uri = URI.parse(conn_string)
35       scheme = uri.scheme
36       c = adapter_class(scheme)
37       uri_options = c.send(:uri_to_options, uri)
38       uri.query.split('&').map{|s| s.split('=')}.each{|k,v| uri_options[k.to_sym] = v if k && !k.empty?} unless uri.query.to_s.strip.empty?
39       uri_options.to_a.each{|k,v| uri_options[k] = (defined?(URI::DEFAULT_PARSER) ? URI::DEFAULT_PARSER : URI).unescape(v) if v.is_a?(String)}
40       opts = uri_options.merge(opts).merge!(:orig_opts=>opts.dup, :uri=>conn_string, :adapter=>scheme)
41     end
42   when Hash
43     opts = conn_string.merge(opts)
44     opts = opts.merge(:orig_opts=>opts.dup)
45     c = adapter_class(opts[:adapter_class] || opts[:adapter] || opts['adapter'])
46   else
47     raise Error, "Sequel::Database.connect takes either a Hash or a String, given: #{conn_string.inspect}"
48   end
49 
50   opts = opts.inject({}) do |m, (k,v)|
51     k = :user if k.to_s == 'username'
52     m[k.to_sym] = v
53     m
54   end
55 
56   begin
57     db = c.new(opts)
58     db.test_connection if db.send(:typecast_value_boolean, opts.fetch(:test, true))
59     if block_given?
60       return yield(db)
61     end
62   ensure
63     if block_given?
64       db.disconnect if db
65       Sequel.synchronize{::Sequel::DATABASES.delete(db)}
66     end
67   end
68   db
69 end
load_adapter(scheme, opts=OPTS) click to toggle source

Load the adapter from the file system. Raises Sequel::AdapterNotFound if the adapter cannot be loaded, or if the adapter isn't registered correctly after being loaded. Options:

:map

The Hash in which to look for an already loaded adapter (defaults to ADAPTER_MAP).

:subdir

The subdirectory of sequel/adapters to look in, only to be used for loading subadapters.

    # File lib/sequel/database/connecting.rb
 77 def self.load_adapter(scheme, opts=OPTS)
 78   map = opts[:map] || ADAPTER_MAP
 79   if subdir = opts[:subdir]
 80     file = "#{subdir}/#{scheme}"
 81   else
 82     file = scheme
 83   end
 84   
 85   unless obj = Sequel.synchronize{map[scheme]}
 86     # attempt to load the adapter file
 87     begin
 88       require "sequel/adapters/#{file}"
 89     rescue LoadError => e
 90       # If subadapter file doesn't exist, just return,
 91       # using the main adapter class without database customizations.
 92       return if subdir
 93       raise Sequel.convert_exception_class(e, AdapterNotFound)
 94     end
 95     
 96     # make sure we actually loaded the adapter
 97     unless obj = Sequel.synchronize{map[scheme]}
 98       raise AdapterNotFound, "Could not load #{file} adapter: adapter class not registered in ADAPTER_MAP"
 99     end
100   end
101 
102   obj
103 end
set_shared_adapter_scheme(scheme, mod) click to toggle source

Sets the given module as the shared adapter module for the given scheme. Used to register shared adapters for use by the mock adapter. Example:

# in file sequel/adapters/shared/mydb.rb
module Sequel::MyDB
  Sequel::Database.set_shared_adapter_scheme :mydb, self

  def self.mock_adapter_setup(db)
    # ...
  end

  module DatabaseMethods
    # ...
  end

  module DatasetMethods
    # ...
  end
end

would allow the mock adapter to return a Database instance that supports the MyDB syntax via:

Sequel.connect('mock://mydb')
    # File lib/sequel/database/connecting.rb
147 def self.set_shared_adapter_scheme(scheme, mod)
148   Sequel.synchronize{SHARED_ADAPTER_MAP[scheme] = mod}
149 end

Public Instance Methods

adapter_scheme() click to toggle source

Returns the scheme symbol for this instance's class, which reflects which adapter is being used. In some cases, this can be the same as the database_type (for native adapters), in others (i.e. adapters with subadapters), it will be different.

Sequel.connect('jdbc:postgres://...').adapter_scheme
# => :jdbc
    # File lib/sequel/database/connecting.rb
162 def adapter_scheme
163   self.class.adapter_scheme
164 end
add_servers(servers) click to toggle source

Dynamically add new servers or modify server options at runtime. Also adds new servers to the connection pool. Only usable when using a sharded connection pool.

servers argument should be a hash with server name symbol keys and hash or proc values. If a servers key is already in use, it's value is overridden with the value provided.

DB.add_servers(f: {host: "hash_host_f"})
    # File lib/sequel/database/connecting.rb
174 def add_servers(servers)
175   unless sharded?
176     raise Error, "cannot call Database#add_servers on a Database instance that does not use a sharded connection pool"
177   end
178 
179   h = @opts[:servers]
180   Sequel.synchronize{h.merge!(servers)}
181   @pool.add_servers(servers.keys)
182 end
database_type() click to toggle source

The database type for this database object, the same as the adapter scheme by default. Should be overridden in adapters (especially shared adapters) to be the correct type, so that even if two separate Database objects are using different adapters you can tell that they are using the same database type. Even better, you can tell that two Database objects that are using the same adapter are connecting to different database types.

Sequel.connect('jdbc:postgres://...').database_type
# => :postgres
    # File lib/sequel/database/connecting.rb
193 def database_type
194   adapter_scheme
195 end
disconnect(opts = OPTS) click to toggle source

Disconnects all available connections from the connection pool. Any connections currently in use will not be disconnected. Options:

:server

Should be a symbol specifing the server to disconnect from,

or an array of symbols to specify multiple servers.

Example:

DB.disconnect # All servers
DB.disconnect(server: :server1) # Single server
DB.disconnect(server: [:server1, :server2]) # Multiple servers
    # File lib/sequel/database/connecting.rb
207 def disconnect(opts = OPTS)
208   pool.disconnect(opts)
209 end
disconnect_connection(conn) click to toggle source

Should only be called by the connection pool code to disconnect a connection. By default, calls the close method on the connection object, since most adapters use that, but should be overwritten on other adapters.

    # File lib/sequel/database/connecting.rb
214 def disconnect_connection(conn)
215   conn.close
216 end
remove_servers(*servers) click to toggle source

Dynamically remove existing servers from the connection pool. Only usable when using a sharded connection pool

servers should be symbols or arrays of symbols. If a nonexistent server is specified, it is ignored. If no servers have been specified for this database, no changes are made. If you attempt to remove the :default server, an error will be raised.

DB.remove_servers(:f1, :f2)
    # File lib/sequel/database/connecting.rb
227 def remove_servers(*servers)
228   unless sharded?
229     raise Error, "cannot call Database#remove_servers on a Database instance that does not use a sharded connection pool"
230   end
231 
232   h = @opts[:servers]
233   servers.flatten.each{|s| Sequel.synchronize{h.delete(s)}}
234   @pool.remove_servers(servers)
235 end
servers() click to toggle source

An array of servers/shards for this Database object.

DB.servers # Unsharded: => [:default]
DB.servers # Sharded:   => [:default, :server1, :server2]
    # File lib/sequel/database/connecting.rb
241 def servers
242   pool.servers
243 end
single_threaded?() click to toggle source

Returns true if the database is using a single-threaded connection pool.

    # File lib/sequel/database/connecting.rb
246 def single_threaded?
247   @single_threaded
248 end
synchronize(server=nil) { |conn| ... } click to toggle source

:nocov:

    # File lib/sequel/database/connecting.rb
252 def synchronize(server=nil)
253   @pool.hold(server || :default){|conn| yield conn}
254 end
test_connection(server=nil) click to toggle source

Attempts to acquire a database connection. Returns true if successful. Will probably raise an Error if unsuccessful. If a server argument is given, attempts to acquire a database connection to the given server/shard.

    # File lib/sequel/database/connecting.rb
278 def test_connection(server=nil)
279   synchronize(server){|conn|}
280   true
281 end
valid_connection?(conn) click to toggle source

Check whether the given connection is currently valid, by running a query against it. If the query fails, the connection should probably be removed from the connection pool.

    # File lib/sequel/database/connecting.rb
287 def valid_connection?(conn)
288   sql = valid_connection_sql
289   begin
290     log_connection_execute(conn, sql)
291   rescue Sequel::DatabaseError, *database_error_classes
292     false
293   else
294     true
295   end
296 end

Private Instance Methods

connection_pool_default_options() click to toggle source

The default options for the connection pool.

    # File lib/sequel/database/connecting.rb
301 def connection_pool_default_options
302   {}
303 end
server_opts(server) click to toggle source

Return the options for the given server by merging the generic options for all server with the specific options for the given server specified in the :servers option.

    # File lib/sequel/database/connecting.rb
308 def server_opts(server)
309   opts = if @opts[:servers] and server_options = @opts[:servers][server]
310     case server_options
311     when Hash
312       @opts.merge(server_options)
313     when Proc
314       @opts.merge(server_options.call(self))
315     else
316       raise Error, 'Server opts should be a hash or proc'
317     end
318   elsif server.is_a?(Hash)
319     @opts.merge(server)
320   else
321     @opts.dup
322   end
323   opts.delete(:servers)
324   opts
325 end
valid_connection_sql() click to toggle source

The SQL query to issue to check if a connection is valid.

    # File lib/sequel/database/connecting.rb
328 def valid_connection_sql
329   @valid_connection_sql ||= select(nil).sql
330 end

5 - Methods that set defaults for created datasets

↑ top

Attributes

dataset_class[R]

The class to use for creating datasets. Should respond to new with the Database argument as the first argument, and an optional options hash.

Public Instance Methods

dataset_class=(c) click to toggle source

If the database has any dataset modules associated with it, use a subclass of the given class that includes the modules as the dataset class.

   # File lib/sequel/database/dataset_defaults.rb
18 def dataset_class=(c)
19   unless @dataset_modules.empty?
20     c = Class.new(c)
21     @dataset_modules.each{|m| c.send(:include, m)}
22   end
23   @dataset_class = c
24   reset_default_dataset
25 end
extend_datasets(mod=nil, &block) click to toggle source

Equivalent to extending all datasets produced by the database with a module. What it actually does is use a subclass of the current dataset_class as the new dataset_class, and include the module in the subclass. Instead of a module, you can provide a block that is used to create an anonymous module.

This allows you to override any of the dataset methods even if they are defined directly on the dataset class that this Database object uses.

If a block is given, a Dataset::DatasetModule instance is created, allowing for the easy creation of named dataset methods that will do caching.

Examples:

# Introspect columns for all of DB's datasets
DB.extend_datasets(Sequel::ColumnsIntrospection)

# Trace all SELECT queries by printing the SQL and the full backtrace
DB.extend_datasets do
  def fetch_rows(sql)
    puts sql
    puts caller
    super
  end
end

# Add some named dataset methods
DB.extend_datasets do
  order :by_id, :id
  select :with_id_and_name, :id, :name
  where :active, :active
end

DB[:table].active.with_id_and_name.by_id
# SELECT id, name FROM table WHERE active ORDER BY id
   # File lib/sequel/database/dataset_defaults.rb
62 def extend_datasets(mod=nil, &block)
63   raise(Error, "must provide either mod or block, not both") if mod && block
64   mod = Dataset::DatasetModule.new(&block) if block
65   if @dataset_modules.empty?
66    @dataset_modules = [mod]
67    @dataset_class = Class.new(@dataset_class)
68   else
69    @dataset_modules << mod
70   end
71   @dataset_class.send(:include, mod)
72   reset_default_dataset
73 end

Private Instance Methods

dataset_class_default() click to toggle source

The default dataset class to use for the database

   # File lib/sequel/database/dataset_defaults.rb
78 def dataset_class_default
79   Sequel::Dataset
80 end
quote_identifiers_default() click to toggle source

Whether to quote identifiers by default for this database, true by default.

   # File lib/sequel/database/dataset_defaults.rb
89 def quote_identifiers_default
90   true
91 end
reset_default_dataset() click to toggle source

Reset the default dataset used by most Database methods that create datasets.

   # File lib/sequel/database/dataset_defaults.rb
83 def reset_default_dataset
84   Sequel.synchronize{@symbol_literal_cache.clear}
85   @default_dataset = dataset
86 end

6 - Methods relating to logging

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Attributes

log_connection_info[RW]

Whether to include information about the connection in use when logging queries.

log_warn_duration[RW]

Numeric specifying the duration beyond which queries are logged at warn level instead of info level.

loggers[RW]

Array of SQL loggers to use for this database.

sql_log_level[RW]

Log level at which to log SQL queries. This is actually the method sent to the logger, so it should be the method name symbol. The default is :info, it can be set to :debug to log at DEBUG level.

Public Instance Methods

log_connection_yield(sql, conn, args=nil) { || ... } click to toggle source

Yield to the block, logging any errors at error level to all loggers, and all other queries with the duration at warn or info level.

   # File lib/sequel/database/logging.rb
37 def log_connection_yield(sql, conn, args=nil)
38   return yield if @loggers.empty?
39   sql = "#{connection_info(conn) if conn && log_connection_info}#{sql}#{"; #{args.inspect}" if args}"
40   timer = Sequel.start_timer
41 
42   begin
43     yield
44   rescue => e
45     log_exception(e, sql)
46     raise
47   ensure
48     log_duration(Sequel.elapsed_seconds_since(timer), sql) unless e
49   end
50 end
log_exception(exception, message) click to toggle source

Log a message at error level, with information about the exception.

   # File lib/sequel/database/logging.rb
26 def log_exception(exception, message)
27   log_each(:error, "#{exception.class}: #{exception.message.strip if exception.message}: #{message}")
28 end
log_info(message, args=nil) click to toggle source

Log a message at level info to all loggers.

   # File lib/sequel/database/logging.rb
31 def log_info(message, args=nil)
32   log_each(:info, args ? "#{message}; #{args.inspect}" : message)
33 end
logger=(logger) click to toggle source

Remove any existing loggers and just use the given logger:

DB.logger = Logger.new($stdout)
   # File lib/sequel/database/logging.rb
55 def logger=(logger)
56   @loggers = Array(logger)
57 end

Private Instance Methods

connection_info(conn) click to toggle source

String including information about the connection, for use when logging connection info.

   # File lib/sequel/database/logging.rb
63 def connection_info(conn)
64   "(conn: #{conn.__id__}) "
65 end
log_connection_execute(conn, sql) click to toggle source

Log the given SQL and then execute it on the connection, used by the transaction code.

   # File lib/sequel/database/logging.rb
69 def log_connection_execute(conn, sql)
70   log_connection_yield(sql, conn){conn.public_send(connection_execute_method, sql)}
71 end
log_duration(duration, message) click to toggle source

Log message with message prefixed by duration at info level, or warn level if duration is greater than log_warn_duration.

   # File lib/sequel/database/logging.rb
75 def log_duration(duration, message)
76   log_each((lwd = log_warn_duration and duration >= lwd) ? :warn : sql_log_level, "(#{sprintf('%0.6fs', duration)}) #{message}")
77 end
log_each(level, message) click to toggle source

Log message at level (which should be :error, :warn, or :info) to all loggers.

   # File lib/sequel/database/logging.rb
81 def log_each(level, message)
82   @loggers.each{|logger| logger.public_send(level, message)}
83 end

7 - Miscellaneous methods

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Constants

CHECK_CONSTRAINT_SQLSTATES
DEFAULT_DATABASE_ERROR_REGEXPS

Empty exception regexp to class map, used by default if Sequel doesn't have specific support for the database in use.

DEFAULT_STRING_COLUMN_SIZE

The general default size for string columns for all Sequel::Database instances.

EXTENSIONS

Hash of extension name symbols to callable objects to load the extension into the Database object (usually by extending it with a module defined in the extension).

FOREIGN_KEY_CONSTRAINT_SQLSTATES
NOT_NULL_CONSTRAINT_SQLSTATES
SCHEMA_TYPE_CLASSES

Mapping of schema type symbols to class or arrays of classes for that symbol.

SERIALIZATION_CONSTRAINT_SQLSTATES
UNIQUE_CONSTRAINT_SQLSTATES

Attributes

default_string_column_size[RW]

The specific default size of string columns for this Sequel::Database, usually 255 by default.

opts[R]

The options hash for this database

timezone[W]

Set the timezone to use for this database, overridding Sequel.database_timezone.

Public Class Methods

after_initialize(&block) click to toggle source

Register a hook that will be run when a new Database is instantiated. It is called with the new database handle.

   # File lib/sequel/database/misc.rb
34 def self.after_initialize(&block)
35   raise Error, "must provide block to after_initialize" unless block
36   Sequel.synchronize do
37     previous = @initialize_hook
38     @initialize_hook = Proc.new do |db|
39       previous.call(db)
40       block.call(db)
41     end
42   end
43 end
extension(*extensions) click to toggle source

Apply an extension to all Database objects created in the future.

   # File lib/sequel/database/misc.rb
46 def self.extension(*extensions)
47   after_initialize{|db| db.extension(*extensions)}
48 end
new(opts = OPTS) click to toggle source

Constructs a new instance of a database connection with the specified options hash.

Accepts the following options:

:cache_schema

Whether schema should be cached for this Database instance

:default_string_column_size

The default size of string columns, 255 by default.

:keep_reference

Whether to keep a reference to this instance in Sequel::DATABASES, true by default.

:logger

A specific logger to use.

:loggers

An array of loggers to use.

:log_connection_info

Whether connection information should be logged when logging queries.

:log_warn_duration

The number of elapsed seconds after which queries should be logged at warn level.

:name

A name to use for the Database object.

:preconnect

Whether to automatically connect to the maximum number of servers. Can use a valid of 'concurrently' to preconnect in separate threads.

:quote_identifiers

Whether to quote identifiers.

:servers

A hash specifying a server/shard specific options, keyed by shard symbol .

:single_threaded

Whether to use a single-threaded connection pool.

:sql_log_level

Method to use to log SQL to a logger, :info by default.

All options given are also passed to the connection pool.

    # File lib/sequel/database/misc.rb
114 def initialize(opts = OPTS)
115   @opts ||= opts
116   @opts = connection_pool_default_options.merge(@opts)
117   @loggers = Array(@opts[:logger]) + Array(@opts[:loggers])
118   @opts[:servers] = {} if @opts[:servers].is_a?(String)
119   @sharded = !!@opts[:servers]
120   @opts[:adapter_class] = self.class
121   @opts[:single_threaded] = @single_threaded = typecast_value_boolean(@opts.fetch(:single_threaded, Sequel.single_threaded))
122   @default_string_column_size = @opts[:default_string_column_size] || DEFAULT_STRING_COLUMN_SIZE
123 
124   @schemas = {}
125   @prepared_statements = {}
126   @transactions = {}
127   @symbol_literal_cache = {}
128 
129   @timezone = nil
130 
131   @dataset_class = dataset_class_default
132   @cache_schema = typecast_value_boolean(@opts.fetch(:cache_schema, true))
133   @dataset_modules = []
134   @loaded_extensions = []
135   @schema_type_classes = SCHEMA_TYPE_CLASSES.dup
136 
137   self.sql_log_level = @opts[:sql_log_level] ? @opts[:sql_log_level].to_sym : :info
138   self.log_warn_duration = @opts[:log_warn_duration]
139   self.log_connection_info = typecast_value_boolean(@opts[:log_connection_info])
140 
141   @pool = ConnectionPool.get_pool(self, @opts)
142 
143   reset_default_dataset
144   adapter_initialize
145 
146   unless typecast_value_boolean(@opts[:keep_reference]) == false
147     Sequel.synchronize{::Sequel::DATABASES.push(self)}
148   end
149   Sequel::Database.run_after_initialize(self)
150   if typecast_value_boolean(@opts[:preconnect]) && @pool.respond_to?(:preconnect, true)
151     concurrent = typecast_value_string(@opts[:preconnect]) == "concurrently"
152     @pool.send(:preconnect, concurrent)
153   end
154 
155   case exts = @opts[:extensions]
156   when String
157     extension(*exts.split(',').map(&:to_sym))
158   when Array
159     extension(*exts)
160   when Symbol
161     extension(exts)
162   when nil
163     # nothing
164   else
165     raise Error, "unsupported Database :extensions option: #{@opts[:extensions].inspect}"
166   end
167 end
register_extension(ext, mod=nil, &block) click to toggle source

Register an extension callback for Database objects. ext should be the extension name symbol, and mod should either be a Module that the database is extended with, or a callable object called with the database object. If mod is not provided, a block can be provided and is treated as the mod object.

   # File lib/sequel/database/misc.rb
55 def self.register_extension(ext, mod=nil, &block)
56   if mod
57     raise(Error, "cannot provide both mod and block to Database.register_extension") if block
58     if mod.is_a?(Module)
59       block = proc{|db| db.extend(mod)}
60     else
61       block = mod
62     end
63   end
64   Sequel.synchronize{EXTENSIONS[ext] = block}
65 end
run_after_initialize(instance) click to toggle source

Run the after_initialize hook for the given instance.

   # File lib/sequel/database/misc.rb
68 def self.run_after_initialize(instance)
69   @initialize_hook.call(instance)
70 end

Private Class Methods

uri_to_options(uri) click to toggle source

Converts a uri to an options hash. These options are then passed to a newly created database object.

   # File lib/sequel/database/misc.rb
74 def self.uri_to_options(uri)
75   {
76     :user => uri.user,
77     :password => uri.password,
78     :port => uri.port,
79     :host => uri.hostname,
80     :database => (m = /\/(.*)/.match(uri.path)) && (m[1])
81   }
82 end

Public Instance Methods

cast_type_literal(type) click to toggle source

Cast the given type to a literal type

DB.cast_type_literal(Float) # double precision
DB.cast_type_literal(:foo)  # foo
    # File lib/sequel/database/misc.rb
194 def cast_type_literal(type)
195   type_literal(:type=>type)
196 end
extension(*exts) click to toggle source

Load an extension into the receiver. In addition to requiring the extension file, this also modifies the database to work with the extension (usually extending it with a module defined in the extension file). If no related extension file exists or the extension does not have specific support for Database objects, an Error will be raised. Returns self.

    # File lib/sequel/database/misc.rb
203 def extension(*exts)
204   Sequel.extension(*exts)
205   exts.each do |ext|
206     if pr = Sequel.synchronize{EXTENSIONS[ext]}
207       unless Sequel.synchronize{@loaded_extensions.include?(ext)}
208         Sequel.synchronize{@loaded_extensions << ext}
209         pr.call(self)
210       end
211     else
212       raise(Error, "Extension #{ext} does not have specific support handling individual databases (try: Sequel.extension #{ext.inspect})")
213     end
214   end
215   self
216 end
freeze() click to toggle source

Freeze internal data structures for the Database instance.

Calls superclass method
    # File lib/sequel/database/misc.rb
170 def freeze
171   valid_connection_sql
172   metadata_dataset
173   @opts.freeze
174   @loggers.freeze
175   @pool.freeze
176   @dataset_class.freeze
177   @dataset_modules.freeze
178   @schema_type_classes.freeze
179   @loaded_extensions.freeze
180   metadata_dataset
181   super
182 end
from_application_timestamp(v) click to toggle source

Convert the given timestamp from the application's timezone, to the databases's timezone or the default database timezone if the database does not have a timezone.

    # File lib/sequel/database/misc.rb
221 def from_application_timestamp(v)
222   Sequel.convert_output_timestamp(v, timezone)
223 end
inspect() click to toggle source

Returns a string representation of the database object including the class name and connection URI and options used when connecting (if any).

    # File lib/sequel/database/misc.rb
227 def inspect
228   a = []
229   a << uri.inspect if uri
230   if (oo = opts[:orig_opts]) && !oo.empty?
231     a << oo.inspect
232   end
233   "#<#{self.class}: #{a.join(' ')}>"
234 end
literal(v) click to toggle source

Proxy the literal call to the dataset.

DB.literal(1)   # 1
DB.literal(:a)  # a
DB.literal('a') # 'a'
    # File lib/sequel/database/misc.rb
241 def literal(v)
242   schema_utility_dataset.literal(v)
243 end
literal_symbol(sym) click to toggle source

Return the literalized version of the symbol if cached, or nil if it is not cached.

    # File lib/sequel/database/misc.rb
247 def literal_symbol(sym)
248   Sequel.synchronize{@symbol_literal_cache[sym]}
249 end
literal_symbol_set(sym, lit) click to toggle source

Set the cached value of the literal symbol.

    # File lib/sequel/database/misc.rb
252 def literal_symbol_set(sym, lit)
253   Sequel.synchronize{@symbol_literal_cache[sym] = lit}
254 end
prepared_statement(name) click to toggle source

Synchronize access to the prepared statements cache.

    # File lib/sequel/database/misc.rb
257 def prepared_statement(name)
258   Sequel.synchronize{prepared_statements[name]}
259 end
quote_identifier(v) click to toggle source

Proxy the quote_identifier method to the dataset, useful for quoting unqualified identifiers for use outside of datasets.

    # File lib/sequel/database/misc.rb
264 def quote_identifier(v)
265   schema_utility_dataset.quote_identifier(v)
266 end
schema_type_class(type) click to toggle source

Return ruby class or array of classes for the given type symbol.

    # File lib/sequel/database/misc.rb
269 def schema_type_class(type)
270   @schema_type_classes[type]
271 end
serial_primary_key_options() click to toggle source

Default serial primary key options, used by the table creation code.

    # File lib/sequel/database/misc.rb
274 def serial_primary_key_options
275   {:primary_key => true, :type => Integer, :auto_increment => true}
276 end
set_prepared_statement(name, ps) click to toggle source

Cache the prepared statement object at the given name.

    # File lib/sequel/database/misc.rb
279 def set_prepared_statement(name, ps)
280   Sequel.synchronize{prepared_statements[name] = ps}
281 end
sharded?() click to toggle source

Whether this database instance uses multiple servers, either for sharding or for master/slave.

    # File lib/sequel/database/misc.rb
285 def sharded?
286   @sharded
287 end
timezone() click to toggle source

The timezone to use for this database, defaulting to Sequel.database_timezone.

    # File lib/sequel/database/misc.rb
290 def timezone
291   @timezone || Sequel.database_timezone
292 end
to_application_timestamp(v) click to toggle source

Convert the given timestamp to the application's timezone, from the databases's timezone or the default database timezone if the database does not have a timezone.

    # File lib/sequel/database/misc.rb
297 def to_application_timestamp(v)
298   Sequel.convert_timestamp(v, timezone)
299 end
typecast_value(column_type, value) click to toggle source

Typecast the value to the given column_type. Calls typecast_value_#{column_type} if the method exists, otherwise returns the value. This method should raise Sequel::InvalidValue if assigned value is invalid.

    # File lib/sequel/database/misc.rb
306 def typecast_value(column_type, value)
307   return nil if value.nil?
308   meth = "typecast_value_#{column_type}"
309   begin
310     # Allow calling private methods as per-type typecasting methods are private
311     respond_to?(meth, true) ? send(meth, value) : value
312   rescue ArgumentError, TypeError => e
313     raise Sequel.convert_exception_class(e, InvalidValue)
314   end
315 end
uri() click to toggle source

Returns the URI use to connect to the database. If a URI was not used when connecting, returns nil.

    # File lib/sequel/database/misc.rb
319 def uri
320   opts[:uri]
321 end
url() click to toggle source

Explicit alias of uri for easier subclassing.

    # File lib/sequel/database/misc.rb
324 def url
325   uri
326 end

Private Instance Methods

_typecast_value_string_to_decimal(value) click to toggle source

Typecast a string to a BigDecimal

    # File lib/sequel/database/misc.rb
463 def _typecast_value_string_to_decimal(value)
464   BigDecimal(value)
465 end
adapter_initialize() click to toggle source

Per adapter initialization method, empty by default.

    # File lib/sequel/database/misc.rb
331 def adapter_initialize
332 end
blank_object?(obj) click to toggle source

Returns true when the object is considered blank. The only objects that are blank are nil, false, strings with all whitespace, and ones that respond true to empty?

    # File lib/sequel/database/misc.rb
338 def blank_object?(obj)
339   return obj.blank? if obj.respond_to?(:blank?)
340   case obj
341   when NilClass, FalseClass
342     true
343   when Numeric, TrueClass
344     false
345   when String
346     obj.strip.empty?
347   else
348     obj.respond_to?(:empty?) ? obj.empty? : false
349   end
350 end
database_error_class(exception, opts) click to toggle source

Return the Sequel::DatabaseError subclass to wrap the given exception in.

    # File lib/sequel/database/misc.rb
361 def database_error_class(exception, opts)
362   database_specific_error_class(exception, opts) || DatabaseError
363 end
database_error_regexps() click to toggle source

An enumerable yielding pairs of regexps and exception classes, used to match against underlying driver exception messages in order to raise a more specific Sequel::DatabaseError subclass.

    # File lib/sequel/database/misc.rb
355 def database_error_regexps
356   DEFAULT_DATABASE_ERROR_REGEXPS
357 end
database_exception_sqlstate(exception, opts) click to toggle source

Return the SQLState for the given exception, if one can be determined

    # File lib/sequel/database/misc.rb
366 def database_exception_sqlstate(exception, opts)
367   nil
368 end
database_specific_error_class(exception, opts) click to toggle source

Return a specific Sequel::DatabaseError exception class if one is appropriate for the underlying exception, or nil if there is no specific exception class.

    # File lib/sequel/database/misc.rb
373 def database_specific_error_class(exception, opts)
374   return DatabaseDisconnectError if disconnect_error?(exception, opts)
375 
376   if sqlstate = database_exception_sqlstate(exception, opts)
377     if klass = database_specific_error_class_from_sqlstate(sqlstate)
378       return klass
379     end
380   else
381     database_error_regexps.each do |regexp, klss|
382       return klss if exception.message =~ regexp
383     end
384   end
385 
386   nil
387 end
database_specific_error_class_from_sqlstate(sqlstate) click to toggle source

Given the SQLState, return the appropriate DatabaseError subclass.

    # File lib/sequel/database/misc.rb
395 def database_specific_error_class_from_sqlstate(sqlstate)
396   case sqlstate
397   when *NOT_NULL_CONSTRAINT_SQLSTATES
398     NotNullConstraintViolation
399   when *FOREIGN_KEY_CONSTRAINT_SQLSTATES
400     ForeignKeyConstraintViolation
401   when *UNIQUE_CONSTRAINT_SQLSTATES
402     UniqueConstraintViolation
403   when *CHECK_CONSTRAINT_SQLSTATES
404     CheckConstraintViolation
405   when *SERIALIZATION_CONSTRAINT_SQLSTATES
406     SerializationFailure
407   end
408 end
disconnect_error?(exception, opts) click to toggle source

Return true if exception represents a disconnect error, false otherwise.

    # File lib/sequel/database/misc.rb
411 def disconnect_error?(exception, opts)
412   opts[:disconnect]
413 end
raise_error(exception, opts=OPTS) click to toggle source

Convert the given exception to an appropriate Sequel::DatabaseError subclass, keeping message and backtrace.

    # File lib/sequel/database/misc.rb
417 def raise_error(exception, opts=OPTS)
418   if !opts[:classes] || Array(opts[:classes]).any?{|c| exception.is_a?(c)}
419     raise Sequel.convert_exception_class(exception, database_error_class(exception, opts))
420   else
421     raise exception
422   end
423 end
typecast_value_blob(value) click to toggle source

Typecast the value to an SQL::Blob

    # File lib/sequel/database/misc.rb
426 def typecast_value_blob(value)
427   value.is_a?(Sequel::SQL::Blob) ? value : Sequel::SQL::Blob.new(value)
428 end
typecast_value_boolean(value) click to toggle source

Typecast the value to true, false, or nil

    # File lib/sequel/database/misc.rb
431 def typecast_value_boolean(value)
432   case value
433   when false, 0, "0", /\Af(alse)?\z/i, /\Ano?\z/i
434     false
435   else
436     blank_object?(value) ? nil : true
437   end
438 end
typecast_value_date(value) click to toggle source

Typecast the value to a Date

    # File lib/sequel/database/misc.rb
441 def typecast_value_date(value)
442   case value
443   when DateTime, Time
444     Date.new(value.year, value.month, value.day)
445   when Date
446     value
447   when String
448     Sequel.string_to_date(value)
449   when Hash
450     Date.new(*[:year, :month, :day].map{|x| (value[x] || value[x.to_s]).to_i})
451   else
452     raise InvalidValue, "invalid value for Date: #{value.inspect}"
453   end
454 end
typecast_value_datetime(value) click to toggle source

Typecast the value to a DateTime or Time depending on Sequel.datetime_class

    # File lib/sequel/database/misc.rb
457 def typecast_value_datetime(value)
458   Sequel.typecast_to_application_timestamp(value)
459 end
typecast_value_decimal(value) click to toggle source

Typecast the value to a BigDecimal

    # File lib/sequel/database/misc.rb
486 def typecast_value_decimal(value)
487   case value
488   when BigDecimal
489     value
490   when Numeric
491     BigDecimal(value.to_s)
492   when String
493     _typecast_value_string_to_decimal(value)
494   else
495     raise InvalidValue, "invalid value for BigDecimal: #{value.inspect}"
496   end
497 end
typecast_value_float(value) click to toggle source

Typecast the value to a Float

    # File lib/sequel/database/misc.rb
500 def typecast_value_float(value)
501   Float(value)
502 end
typecast_value_integer(value) click to toggle source

Typecast the value to an Integer

    # File lib/sequel/database/misc.rb
505 def typecast_value_integer(value)
506   (value.is_a?(String) && value =~ /\A0+(\d)/) ? Integer(value, 10) : Integer(value)
507 end
typecast_value_string(value) click to toggle source

Typecast the value to a String

    # File lib/sequel/database/misc.rb
510 def typecast_value_string(value)
511   case value
512   when Hash, Array
513     raise Sequel::InvalidValue, "invalid value for String: #{value.inspect}"
514   else
515     value.to_s
516   end
517 end
typecast_value_time(value) click to toggle source

Typecast the value to a Time

    # File lib/sequel/database/misc.rb
520 def typecast_value_time(value)
521   case value
522   when Time
523     if value.is_a?(SQLTime)
524       value
525     else
526       SQLTime.create(value.hour, value.min, value.sec, value.nsec/1000.0)
527     end
528   when String
529     Sequel.string_to_time(value)
530   when Hash
531     SQLTime.create(*[:hour, :minute, :second].map{|x| (value[x] || value[x.to_s]).to_i})
532   else
533     raise Sequel::InvalidValue, "invalid value for Time: #{value.inspect}"
534   end
535 end

8 - Methods related to database transactions

↑ top

Constants

TRANSACTION_ISOLATION_LEVELS

Attributes

transaction_isolation_level[RW]

The default transaction isolation level for this database, used for all future transactions. For MSSQL, this should be set to something if you ever plan to use the :isolation option to Database#transaction, as on MSSQL if affects all future transactions on the same connection.

Public Instance Methods

after_commit(opts=OPTS) { || ... } click to toggle source

If a transaction is not currently in process, yield to the block immediately. Otherwise, add the block to the list of blocks to call after the currently in progress transaction commits (and only if it commits). Options:

:server

The server/shard to use.

   # File lib/sequel/database/transactions.rb
29 def after_commit(opts=OPTS, &block)
30   raise Error, "must provide block to after_commit" unless block
31   synchronize(opts[:server]) do |conn|
32     if h = _trans(conn)
33       raise Error, "cannot call after_commit in a prepared transaction" if h[:prepare]
34       add_transaction_hook(conn, :after_commit, block)
35     else
36       yield
37     end
38   end
39 end
after_rollback(opts=OPTS, &block) click to toggle source

If a transaction is not currently in progress, ignore the block. Otherwise, add the block to the list of the blocks to call after the currently in progress transaction rolls back (and only if it rolls back). Options:

:server

The server/shard to use.

   # File lib/sequel/database/transactions.rb
46 def after_rollback(opts=OPTS, &block)
47   raise Error, "must provide block to after_rollback" unless block
48   synchronize(opts[:server]) do |conn|
49     if h = _trans(conn)
50       raise Error, "cannot call after_rollback in a prepared transaction" if h[:prepare]
51       add_transaction_hook(conn, :after_rollback, block)
52     end
53   end
54 end
in_transaction?(opts=OPTS) click to toggle source

Return true if already in a transaction given the options, false otherwise. Respects the :server option for selecting a shard.

   # File lib/sequel/database/transactions.rb
59 def in_transaction?(opts=OPTS)
60   synchronize(opts[:server]){|conn| !!_trans(conn)}
61 end
rollback_checker(opts=OPTS) click to toggle source

Returns a proc that you can call to check if the transaction has been rolled back. The proc will return nil if the transaction is still in progress, true if the transaction was rolled back, and false if it was committed. Raises an Error if called outside a transaction. Respects the :server option for selecting a shard.

   # File lib/sequel/database/transactions.rb
69 def rollback_checker(opts=OPTS)
70   synchronize(opts[:server]) do |conn|
71     raise Error, "not in a transaction" unless t = _trans(conn)
72     t[:rollback_checker] ||= proc{Sequel.synchronize{t[:rolled_back]}}
73   end
74 end
transaction(opts=OPTS) { |conn| ... } click to toggle source

Starts a database transaction. When a database transaction is used, either all statements are successful or none of the statements are successful. Note that MySQL MyISAM tables do not support transactions.

The following general options are respected:

:auto_savepoint

Automatically use a savepoint for Database#transaction calls inside this transaction block.

:isolation

The transaction isolation level to use for this transaction, should be :uncommitted, :committed, :repeatable, or :serializable, used if given and the database/adapter supports customizable transaction isolation levels.

:num_retries

The number of times to retry if the :retry_on option is used. The default is 5 times. Can be set to nil to retry indefinitely, but that is not recommended.

:before_retry

Proc to execute before rertrying if the :retry_on option is used. Called with two arguments: the number of retry attempts (counting the current one) and the error the last attempt failed with.

:prepare

A string to use as the transaction identifier for a prepared transaction (two-phase commit), if the database/adapter supports prepared transactions.

:retry_on

An exception class or array of exception classes for which to automatically retry the transaction. Can only be set if not inside an existing transaction. Note that this should not be used unless the entire transaction block is idempotent, as otherwise it can cause non-idempotent behavior to execute multiple times.

:rollback

Can the set to :reraise to reraise any Sequel::Rollback exceptions raised, or :always to always rollback even if no exceptions occur (useful for testing).

:server

The server to use for the transaction. Set to :default, :read_only, or whatever symbol you used in the connect string when naming your servers.

:savepoint

Whether to create a new savepoint for this transaction, only respected if the database/adapter supports savepoints. By default Sequel will reuse an existing transaction, so if you want to use a savepoint you must use this option. If the surrounding transaction uses :auto_savepoint, you can set this to false to not use a savepoint. If the value given for this option is :only, it will only create a savepoint if it is inside a transaction.

PostgreSQL specific options:

:deferrable

(9.1+) If present, set to DEFERRABLE if true or NOT DEFERRABLE if false.

:read_only

If present, set to READ ONLY if true or READ WRITE if false.

:synchronous

if non-nil, set synchronous_commit appropriately. Valid values true, :on, false, :off, :local (9.1+), and :remote_write (9.2+).

    # File lib/sequel/database/transactions.rb
123 def transaction(opts=OPTS, &block)
124   opts = Hash[opts]
125   if retry_on = opts[:retry_on]
126     tot_retries = opts.fetch(:num_retries, 5)
127     num_retries = 0 unless tot_retries.nil?
128     begin
129       opts[:retry_on] = nil
130       opts[:retrying] = true
131       transaction(opts, &block)
132     rescue *retry_on => e
133       if num_retries
134         num_retries += 1
135         if num_retries <= tot_retries
136           opts[:before_retry].call(num_retries, e) if opts[:before_retry]
137           retry
138         end
139       else
140         retry
141       end
142       raise
143     end
144   else
145     synchronize(opts[:server]) do |conn|
146       if opts[:savepoint] == :only
147         if supports_savepoints?
148           if _trans(conn)
149             opts[:savepoint] = true
150           else
151             return yield(conn)
152           end
153         else
154           opts[:savepoint] = false
155         end
156       end
157 
158       if already_in_transaction?(conn, opts)
159         if opts[:rollback] == :always && !opts.has_key?(:savepoint)
160           if supports_savepoints? 
161             opts[:savepoint] = true
162           else
163             raise Sequel::Error, "cannot set :rollback=>:always transaction option if already inside a transaction"
164           end
165         end
166 
167         if opts[:savepoint] != false && (stack = _trans(conn)[:savepoints]) && stack.last
168           opts[:savepoint] = true
169         end
170 
171         unless opts[:savepoint]
172           if opts[:retrying]
173             raise Sequel::Error, "cannot set :retry_on options if you are already inside a transaction"
174           end
175           return yield(conn)
176         end
177       end
178 
179       _transaction(conn, opts, &block)
180     end
181   end
182 end

Private Instance Methods

_trans(conn) click to toggle source

Synchronize access to the current transactions, returning the hash of options for the current transaction (if any)

    # File lib/sequel/database/transactions.rb
235 def _trans(conn)
236   Sequel.synchronize{@transactions[conn]}
237 end
_transaction(conn, opts=OPTS) { |conn| ... } click to toggle source

Internal generic transaction method. Any exception raised by the given block will cause the transaction to be rolled back. If the exception is not a Sequel::Rollback, the error will be reraised. If no exception occurs inside the block, the transaction is commited.

    # File lib/sequel/database/transactions.rb
190 def _transaction(conn, opts=OPTS)
191   rollback = opts[:rollback]
192   begin
193     add_transaction(conn, opts)
194     begin_transaction(conn, opts)
195     if rollback == :always
196       begin
197         ret = yield(conn)
198       rescue Exception => e1
199         raise e1
200       ensure
201         raise ::Sequel::Rollback unless e1
202       end
203     else
204       yield(conn)
205     end
206   rescue Exception => e
207     begin
208       rollback_transaction(conn, opts)
209     rescue Exception => e3
210     end
211     transaction_error(e, :conn=>conn, :rollback=>rollback)
212     raise e3 if e3
213     ret
214   ensure
215     begin
216       committed = commit_or_rollback_transaction(e, conn, opts)
217     rescue Exception => e2
218       begin
219         raise_error(e2, :classes=>database_error_classes, :conn=>conn)
220       rescue Sequel::DatabaseError => e4
221         begin
222           rollback_transaction(conn, opts)
223         ensure
224           raise e4
225         end
226       end
227     ensure
228       remove_transaction(conn, committed)
229     end
230   end
231 end
add_transaction(conn, opts) click to toggle source

Add the current thread to the list of active transactions

    # File lib/sequel/database/transactions.rb
240 def add_transaction(conn, opts)
241   hash = transaction_options(conn, opts)
242 
243   if supports_savepoints?
244     if t = _trans(conn)
245       t[:savepoints].push(opts[:auto_savepoint])
246       return
247     else
248       hash[:savepoints] = [opts[:auto_savepoint]]
249       if (prep = opts[:prepare]) && supports_prepared_transactions?
250         hash[:prepare] = prep
251       end
252     end
253   elsif (prep = opts[:prepare]) && supports_prepared_transactions?
254     hash[:prepare] = prep
255   end
256 
257   Sequel.synchronize{@transactions[conn] = hash}
258 end
add_transaction_hook(conn, type, block) click to toggle source

Set the given callable as a hook to be called. Type should be either :after_commit or :after_rollback.

    # File lib/sequel/database/transactions.rb
262 def add_transaction_hook(conn, type, block)
263   hooks = _trans(conn)[type] ||= []
264   hooks << block
265 end
already_in_transaction?(conn, opts) click to toggle source

Whether the given connection is already inside a transaction

    # File lib/sequel/database/transactions.rb
268 def already_in_transaction?(conn, opts)
269   _trans(conn) && (!supports_savepoints? || !opts[:savepoint])
270 end
begin_new_transaction(conn, opts) click to toggle source

Start a new database transaction on the given connection

    # File lib/sequel/database/transactions.rb
289 def begin_new_transaction(conn, opts)
290   log_connection_execute(conn, begin_transaction_sql)
291   set_transaction_isolation(conn, opts)
292 end
begin_savepoint(conn, opts) click to toggle source

Issue query to begin a new savepoint.

    # File lib/sequel/database/transactions.rb
279 def begin_savepoint(conn, opts)
280   log_connection_execute(conn, begin_savepoint_sql(savepoint_level(conn)-1))
281 end
begin_savepoint_sql(depth) click to toggle source

SQL to start a new savepoint

    # File lib/sequel/database/transactions.rb
284 def begin_savepoint_sql(depth)
285   "SAVEPOINT autopoint_#{depth}"
286 end
begin_transaction(conn, opts=OPTS) click to toggle source

Start a new database transaction or a new savepoint on the given connection.

    # File lib/sequel/database/transactions.rb
295 def begin_transaction(conn, opts=OPTS)
296   if supports_savepoints?
297     if savepoint_level(conn) > 1
298       begin_savepoint(conn, opts)
299     else
300       begin_new_transaction(conn, opts)
301     end
302   else
303     begin_new_transaction(conn, opts)
304   end
305 end
begin_transaction_sql() click to toggle source

SQL to BEGIN a transaction.

    # File lib/sequel/database/transactions.rb
308 def begin_transaction_sql
309   'BEGIN'
310 end
commit_or_rollback_transaction(exception, conn, opts) click to toggle source

Whether to commit the current transaction. Thread.current.status is checked because Thread#kill skips rescue blocks (so exception would be nil), but the transaction should still be rolled back. On Ruby 1.9 (but not 2.0+), the thread status will still be “run”, so Thread#kill will erroneously commit the transaction, and there isn't a workaround.

    # File lib/sequel/database/transactions.rb
317 def commit_or_rollback_transaction(exception, conn, opts)
318   if exception
319     false
320   else
321     if Thread.current.status == 'aborting'
322       rollback_transaction(conn, opts)
323       false
324     else
325       commit_transaction(conn, opts)
326       true
327     end
328   end
329 end
commit_savepoint_sql(depth) click to toggle source

SQL to commit a savepoint

    # File lib/sequel/database/transactions.rb
332 def commit_savepoint_sql(depth)
333   "RELEASE SAVEPOINT autopoint_#{depth}"
334 end
commit_transaction(conn, opts=OPTS) click to toggle source

Commit the active transaction on the connection

    # File lib/sequel/database/transactions.rb
337 def commit_transaction(conn, opts=OPTS)
338   if supports_savepoints?
339     depth = savepoint_level(conn)
340     log_connection_execute(conn, depth > 1 ? commit_savepoint_sql(depth-1) : commit_transaction_sql)
341   else
342     log_connection_execute(conn, commit_transaction_sql)
343   end
344 end
commit_transaction_sql() click to toggle source

SQL to COMMIT a transaction.

    # File lib/sequel/database/transactions.rb
347 def commit_transaction_sql
348   'COMMIT'
349 end
connection_execute_method() click to toggle source

Method called on the connection object to execute SQL on the database, used by the transaction code.

    # File lib/sequel/database/transactions.rb
353 def connection_execute_method
354   :execute
355 end
database_error_classes() click to toggle source

Which transaction errors to translate, blank by default.

    # File lib/sequel/database/transactions.rb
358 def database_error_classes
359   []
360 end
remove_transaction(conn, committed) click to toggle source

Remove the current thread from the list of active transactions

    # File lib/sequel/database/transactions.rb
371 def remove_transaction(conn, committed)
372   callbacks = transaction_hooks(conn, committed)
373 
374   if transaction_finished?(conn)
375     h = @transactions[conn]
376     rolled_back = !committed
377     Sequel.synchronize{h[:rolled_back] = rolled_back}
378     Sequel.synchronize{@transactions.delete(conn)}
379   end
380 
381   callbacks.each(&:call) if callbacks
382 end
rollback_savepoint_sql(depth) click to toggle source

SQL to rollback to a savepoint

    # File lib/sequel/database/transactions.rb
385 def rollback_savepoint_sql(depth)
386   "ROLLBACK TO SAVEPOINT autopoint_#{depth}"
387 end
rollback_transaction(conn, opts=OPTS) click to toggle source

Rollback the active transaction on the connection

    # File lib/sequel/database/transactions.rb
390 def rollback_transaction(conn, opts=OPTS)
391   if supports_savepoints?
392     depth = savepoint_level(conn)
393     log_connection_execute(conn, depth > 1 ? rollback_savepoint_sql(depth-1) : rollback_transaction_sql)
394   else
395     log_connection_execute(conn, rollback_transaction_sql)
396   end
397 end
rollback_transaction_sql() click to toggle source

SQL to ROLLBACK a transaction.

    # File lib/sequel/database/transactions.rb
400 def rollback_transaction_sql
401   'ROLLBACK'
402 end
savepoint_level(conn) click to toggle source

Current savepoint level.

    # File lib/sequel/database/transactions.rb
417 def savepoint_level(conn)
418   _trans(conn)[:savepoints].length
419 end
set_transaction_isolation(conn, opts) click to toggle source

Set the transaction isolation level on the given connection

    # File lib/sequel/database/transactions.rb
405 def set_transaction_isolation(conn, opts)
406   if supports_transaction_isolation_levels? and level = opts.fetch(:isolation, transaction_isolation_level)
407     log_connection_execute(conn, set_transaction_isolation_sql(level))
408   end
409 end
set_transaction_isolation_sql(level) click to toggle source

SQL to set the transaction isolation level

    # File lib/sequel/database/transactions.rb
412 def set_transaction_isolation_sql(level)
413   "SET TRANSACTION ISOLATION LEVEL #{TRANSACTION_ISOLATION_LEVELS[level]}"
414 end
transaction_error(e, opts=OPTS) click to toggle source

Raise a database error unless the exception is an Rollback.

    # File lib/sequel/database/transactions.rb
422 def transaction_error(e, opts=OPTS)
423   if e.is_a?(Rollback)
424     raise e if opts[:rollback] == :reraise
425   else
426     raise_error(e, opts.merge(:classes=>database_error_classes))
427   end
428 end
transaction_finished?(conn) click to toggle source

Finish a subtransaction. If savepoints are supported, pops the current tansaction off the savepoint stack.

    # File lib/sequel/database/transactions.rb
432 def transaction_finished?(conn)
433   if supports_savepoints?
434     stack = _trans(conn)[:savepoints]
435     stack.pop
436     stack.empty?
437   else
438     true
439   end
440 end
transaction_hooks(conn, committed) click to toggle source

Retrieve the transaction hooks that should be run for the given connection and commit status.

    # File lib/sequel/database/transactions.rb
364 def transaction_hooks(conn, committed)
365   if !supports_savepoints? || savepoint_level(conn) == 1
366     _trans(conn)[committed ? :after_commit : :after_rollback]
367   end
368 end
transaction_options(conn, opts) click to toggle source

Derive the transaction hash from the options passed to the transaction. Meant to be overridden.

    # File lib/sequel/database/transactions.rb
274 def transaction_options(conn, opts)
275   {}
276 end

9 - Methods that describe what the database supports

↑ top

Public Instance Methods

global_index_namespace?() click to toggle source

Whether the database uses a global namespace for the index, true by default. If false, the indexes are going to be namespaced per table.

   # File lib/sequel/database/features.rb
13 def global_index_namespace?
14   true
15 end
supports_create_table_if_not_exists?() click to toggle source

Whether the database supports CREATE TABLE IF NOT EXISTS syntax, false by default.

   # File lib/sequel/database/features.rb
19 def supports_create_table_if_not_exists?
20   false
21 end
supports_deferrable_constraints?() click to toggle source

Whether the database supports deferrable constraints, false by default as few databases do.

   # File lib/sequel/database/features.rb
25 def supports_deferrable_constraints?
26   false
27 end
supports_deferrable_foreign_key_constraints?() click to toggle source

Whether the database supports deferrable foreign key constraints, false by default as few databases do.

   # File lib/sequel/database/features.rb
31 def supports_deferrable_foreign_key_constraints?
32   supports_deferrable_constraints?
33 end
supports_drop_table_if_exists?() click to toggle source

Whether the database supports DROP TABLE IF EXISTS syntax, false by default.

   # File lib/sequel/database/features.rb
37 def supports_drop_table_if_exists?
38   supports_create_table_if_not_exists?
39 end
supports_foreign_key_parsing?() click to toggle source

Whether the database supports Database#foreign_key_list for parsing foreign keys.

   # File lib/sequel/database/features.rb
43 def supports_foreign_key_parsing?
44   respond_to?(:foreign_key_list)
45 end
supports_index_parsing?() click to toggle source

Whether the database supports Database#indexes for parsing indexes.

   # File lib/sequel/database/features.rb
48 def supports_index_parsing?
49   respond_to?(:indexes)
50 end
supports_partial_indexes?() click to toggle source

Whether the database supports partial indexes (indexes on a subset of a table), false by default.

   # File lib/sequel/database/features.rb
54 def supports_partial_indexes?
55   false
56 end
supports_prepared_transactions?() click to toggle source

Whether the database and adapter support prepared transactions (two-phase commit), false by default.

   # File lib/sequel/database/features.rb
60 def supports_prepared_transactions?
61   false
62 end
supports_savepoints?() click to toggle source

Whether the database and adapter support savepoints, false by default.

   # File lib/sequel/database/features.rb
65 def supports_savepoints?
66   false
67 end
supports_savepoints_in_prepared_transactions?() click to toggle source

Whether the database and adapter support savepoints inside prepared transactions (two-phase commit), false by default.

   # File lib/sequel/database/features.rb
71 def supports_savepoints_in_prepared_transactions?
72   supports_prepared_transactions? && supports_savepoints?
73 end
supports_schema_parsing?() click to toggle source

Whether the database supports schema parsing via Database#schema.

   # File lib/sequel/database/features.rb
76 def supports_schema_parsing?
77   respond_to?(:schema_parse_table, true)
78 end
supports_table_listing?() click to toggle source

Whether the database supports Database#tables for getting list of tables.

   # File lib/sequel/database/features.rb
81 def supports_table_listing?
82   respond_to?(:tables)
83 end
supports_transaction_isolation_levels?() click to toggle source

Whether the database and adapter support transaction isolation levels, false by default.

   # File lib/sequel/database/features.rb
91 def supports_transaction_isolation_levels?
92   false
93 end
supports_transactional_ddl?() click to toggle source

Whether DDL statements work correctly in transactions, false by default.

   # File lib/sequel/database/features.rb
96 def supports_transactional_ddl?
97   false
98 end
supports_view_listing?() click to toggle source

Whether the database supports Database#views for getting list of views.

   # File lib/sequel/database/features.rb
86 def supports_view_listing?
87   respond_to?(:views)
88 end
supports_views_with_check_option?() click to toggle source

Whether CREATE VIEW … WITH CHECK OPTION is supported, false by default.

    # File lib/sequel/database/features.rb
101 def supports_views_with_check_option?
102   !!view_with_check_option_support
103 end
supports_views_with_local_check_option?() click to toggle source

Whether CREATE VIEW … WITH LOCAL CHECK OPTION is supported, false by default.

    # File lib/sequel/database/features.rb
106 def supports_views_with_local_check_option?
107   view_with_check_option_support == :local
108 end

Private Instance Methods

can_add_primary_key_constraint_on_nullable_columns?() click to toggle source

Whether the database supports adding primary key constraints on NULLable columns, automatically making them NOT NULL. If false, the columns must be set NOT NULL before the primary key constraint is added.

    # File lib/sequel/database/features.rb
115 def can_add_primary_key_constraint_on_nullable_columns?
116   true
117 end
folds_unquoted_identifiers_to_uppercase?() click to toggle source

Whether this dataset considers unquoted identifiers as uppercase. True by default as that is the SQL standard

    # File lib/sequel/database/features.rb
121 def folds_unquoted_identifiers_to_uppercase?
122   true
123 end
supports_combining_alter_table_ops?() click to toggle source

Whether the database supports combining multiple alter table operations into a single query, false by default.

    # File lib/sequel/database/features.rb
127 def supports_combining_alter_table_ops?
128   false
129 end
supports_create_or_replace_view?() click to toggle source

Whether the database supports CREATE OR REPLACE VIEW. If not, support will be emulated by dropping the view first. false by default.

    # File lib/sequel/database/features.rb
133 def supports_create_or_replace_view?
134   false
135 end
supports_named_column_constraints?() click to toggle source

Whether the database supports named column constraints. True by default. Those that don't support named column constraints have to have column constraints converted to table constraints if the column constraints have names.

    # File lib/sequel/database/features.rb
141 def supports_named_column_constraints?
142   true
143 end
view_with_check_option_support() click to toggle source

Don't advertise support for WITH CHECK OPTION by default.

    # File lib/sequel/database/features.rb
146 def view_with_check_option_support
147   nil
148 end