module Sequel::Model::DatasetMethods
DatasetMethods
contains methods that all model datasets have.
Public Instance Methods
Assume if a single integer is given that it is a lookup by primary key, and call with_pk
with the argument.
Artist.dataset[1] # SELECT * FROM artists WHERE (id = 1) LIMIT 1
# File lib/sequel/model/base.rb 2037 def [](*args) 2038 if args.length == 1 && (i = args[0]) && i.is_a?(Integer) 2039 with_pk(i) 2040 else 2041 super 2042 end 2043 end
This allows you to call as_hash
without any arguments, which will result in a hash with the primary key value being the key and the model object being the value.
Artist.dataset.as_hash # SELECT * FROM artists # => {1=>#<Artist {:id=>1, ...}>, # 2=>#<Artist {:id=>2, ...}>, # ...}
# File lib/sequel/model/base.rb 2096 def as_hash(key_column=nil, value_column=nil, opts=OPTS) 2097 if key_column 2098 super 2099 else 2100 raise(Sequel::Error, "No primary key for model") unless model && (pk = model.primary_key) 2101 super(pk, value_column, opts) 2102 end 2103 end
Destroy each row in the dataset by instantiating it and then calling destroy on the resulting model object. This isn't as fast as deleting the dataset, which does a single SQL
call, but this runs any destroy hooks on each object in the dataset.
Artist.dataset.destroy # DELETE FROM artists WHERE (id = 1) # DELETE FROM artists WHERE (id = 2) # ...
# File lib/sequel/model/base.rb 2054 def destroy 2055 pr = proc{all(&:destroy).length} 2056 model.use_transactions ? @db.transaction(:server=>opts[:server], &pr) : pr.call 2057 end
If there is no order already defined on this dataset, order it by the primary key and call last.
Album.last # SELECT * FROM albums ORDER BY id DESC LIMIT 1
# File lib/sequel/model/base.rb 2064 def last(*a, &block) 2065 if ds = _primary_key_order 2066 ds.last(*a, &block) 2067 else 2068 super 2069 end 2070 end
The model class associated with this dataset
Artist.dataset.model # => Artist
# File lib/sequel/model/base.rb 2029 def model 2030 @opts[:model] 2031 end
If there is no order already defined on this dataset, order it by the primary key and call paged_each.
Album.paged_each{|row| } # SELECT * FROM albums ORDER BY id LIMIT 1000 OFFSET 0 # SELECT * FROM albums ORDER BY id LIMIT 1000 OFFSET 1000 # SELECT * FROM albums ORDER BY id LIMIT 1000 OFFSET 2000 # ...
# File lib/sequel/model/base.rb 2080 def paged_each(*a, &block) 2081 if ds = _primary_key_order 2082 ds.paged_each(*a, &block) 2083 else 2084 super 2085 end 2086 end
Alias of as_hash
for backwards compatibility.
# File lib/sequel/model/base.rb 2106 def to_hash(*a) 2107 as_hash(*a) 2108 end
Given a primary key value, return the first record in the dataset with that primary key value. If no records matches, returns nil.
# Single primary key Artist.dataset.with_pk(1) # SELECT * FROM artists WHERE (artists.id = 1) LIMIT 1 # Composite primary key Artist.dataset.with_pk([1, 2]) # SELECT * FROM artists WHERE ((artists.id1 = 1) AND (artists.id2 = 2)) LIMIT 1
# File lib/sequel/model/base.rb 2120 def with_pk(pk) 2121 if pk && (loader = _with_pk_loader) 2122 loader.first(*pk) 2123 else 2124 first(model.qualified_primary_key_hash(pk)) 2125 end 2126 end
Same as with_pk
, but raises NoMatchingRow
instead of returning nil if no row matches.
# File lib/sequel/model/base.rb 2130 def with_pk!(pk) 2131 with_pk(pk) || raise(NoMatchingRow.new(self)) 2132 end
Private Instance Methods
If the dataset is not already ordered, and the model has a primary key, return a clone ordered by the primary key.
# File lib/sequel/model/base.rb 2138 def _primary_key_order 2139 if @opts[:order].nil? && model && (pk = model.primary_key) 2140 cached_dataset(:_pk_order_ds){order(*pk)} 2141 end 2142 end
A cached placeholder literalizer, if one exists for the current dataset.
# File lib/sequel/model/base.rb 2145 def _with_pk_loader 2146 cached_placeholder_literalizer(:_with_pk_loader) do |pl| 2147 table = model.table_name 2148 cond = case primary_key = model.primary_key 2149 when Array 2150 primary_key.map{|key| [SQL::QualifiedIdentifier.new(table, key), pl.arg]} 2151 when Symbol 2152 {SQL::QualifiedIdentifier.new(table, primary_key)=>pl.arg} 2153 else 2154 raise(Error, "#{model} does not have a primary key") 2155 end 2156 2157 where(cond).limit(1) 2158 end 2159 end
# File lib/sequel/model/base.rb 2161 def non_sql_option?(key) 2162 super || key == :model 2163 end