GdaVconnectionDataModel

GdaVconnectionDataModel — Virtual connection based on a list of GdaDataModel

Synopsis




                    GdaVconnectionDataModel;
void                (*GdaVConnectionDataModelFunc)      (GdaDataModel *model,
                                                         const gchar *table_name,
                                                         gpointer data);
                    GdaVconnectionDataModelSpec;
GList*              (*GdaVconnectionDataModelCreateColumnsFunc)
                                                        (GdaVconnectionDataModelSpec *);
GdaDataModel*       (*GdaVconnectionDataModelCreateModelFunc)
                                                        (GdaVconnectionDataModelSpec *);
gboolean            gda_vconnection_data_model_add      (GdaVconnectionDataModel *cnc,
                                                         GdaVconnectionDataModelSpec *spec,
                                                         GDestroyNotify spec_free_func,
                                                         const gchar *table_name,
                                                         GError **error);
gboolean            gda_vconnection_data_model_add_model
                                                        (GdaVconnectionDataModel *cnc,
                                                         GdaDataModel *model,
                                                         const gchar *table_name,
                                                         GError **error);
gboolean            gda_vconnection_data_model_remove   (GdaVconnectionDataModel *cnc,
                                                         const gchar *table_name,
                                                         GError **error);
const gchar*        gda_vconnection_data_model_get_table_name
                                                        (GdaVconnectionDataModel *cnc,
                                                         GdaDataModel *model);
GdaDataModel*       gda_vconnection_data_model_get_model
                                                        (GdaVconnectionDataModel *cnc,
                                                         const gchar *table_name);
void                gda_vconnection_data_model_foreach  (GdaVconnectionDataModel *cnc,
                                                         GdaVConnectionDataModelFunc func,
                                                         gpointer data);

Object Hierarchy


  GObject
   +----GdaConnection
         +----GdaVirtualConnection
               +----GdaVconnectionDataModel
                     +----GdaVconnectionHub

Description

the GdaVconnectionDataModel is a virtual connection in which GdaDataModel data models can bas added or removed, each representing a table in the connection.

Note that virtual connections have some inherent limitations [2]due to the implementation.

Details

GdaVconnectionDataModel

typedef struct _GdaVconnectionDataModel GdaVconnectionDataModel;


GdaVConnectionDataModelFunc ()

void                (*GdaVConnectionDataModelFunc)      (GdaDataModel *model,
                                                         const gchar *table_name,
                                                         gpointer data);

model :
table_name :
data :

GdaVconnectionDataModelSpec

typedef struct {
	GdaDataModel                             *data_model;
	GdaVconnectionDataModelCreateColumnsFunc  create_columns_func;
	GdaVconnectionDataModelCreateModelFunc    create_model_func;
} GdaVconnectionDataModelSpec;


GdaVconnectionDataModelCreateColumnsFunc ()

GList*              (*GdaVconnectionDataModelCreateColumnsFunc)
                                                        (GdaVconnectionDataModelSpec *);

Param1 :
Returns :

GdaVconnectionDataModelCreateModelFunc ()

GdaDataModel*       (*GdaVconnectionDataModelCreateModelFunc)
                                                        (GdaVconnectionDataModelSpec *);

Param1 :
Returns :

gda_vconnection_data_model_add ()

gboolean            gda_vconnection_data_model_add      (GdaVconnectionDataModel *cnc,
                                                         GdaVconnectionDataModelSpec *spec,
                                                         GDestroyNotify spec_free_func,
                                                         const gchar *table_name,
                                                         GError **error);

Create a new virtual table named table_name in cnc. The contents of that new table is dictated by what's in spec.

If there is just one GdaDataModel to make appear as a table then the gda_vconnection_data_model_add_model() method is easier to use.

cnc : a GdaVconnectionDataModel connection
spec : a GdaVconnectionDataModelSpec structure
spec_free_func : function to call when freeing spec, or NULL
table_name : the name of the table
error : a place to store errors, or NULL
Returns : TRUE if no error occurred

gda_vconnection_data_model_add_model ()

gboolean            gda_vconnection_data_model_add_model
                                                        (GdaVconnectionDataModel *cnc,
                                                         GdaDataModel *model,
                                                         const gchar *table_name,
                                                         GError **error);

Make model appear as a table named table_name in the cnc connection (as if a "CREATE TABLE..." statement was executed, except that the data contained within model is actually used when table_name's contents is read or written).

For a more general approach, see the gda_vconnection_data_model_add() method.

cnc : a GdaVconnectionDataModel connection
model : a GdaDataModel
table_name : the name of the table
error : a place to store errors, or NULL
Returns : TRUE if no error occurred

gda_vconnection_data_model_remove ()

gboolean            gda_vconnection_data_model_remove   (GdaVconnectionDataModel *cnc,
                                                         const gchar *table_name,
                                                         GError **error);

Remove the table named table_name in the cnc connection (as if a "DROP TABLE..." statement was executed, except that no data gets destroyed as the associated data model remains the same).

cnc : a GdaVconnectionDataModel connection
table_name : the name of the table to remove from cnc
error : a place to store errors, or NULL
Returns : TRUE if no error occurred

gda_vconnection_data_model_get_table_name ()

const gchar*        gda_vconnection_data_model_get_table_name
                                                        (GdaVconnectionDataModel *cnc,
                                                         GdaDataModel *model);

Find the name of the table associated to model in cnc

cnc : a GdaVconnectionDataModel connection
model : a GdaDataModel representing a table within cnc
Returns : the table name, or NULL if not found

gda_vconnection_data_model_get_model ()

GdaDataModel*       gda_vconnection_data_model_get_model
                                                        (GdaVconnectionDataModel *cnc,
                                                         const gchar *table_name);

Find the GdaDataModel object representing the table_name table in cnc

cnc : a GdaVconnectionDataModel connection
table_name : a table name within cnc
Returns : the GdaDataModel, or NULL if no table named table_name exists

gda_vconnection_data_model_foreach ()

void                gda_vconnection_data_model_foreach  (GdaVconnectionDataModel *cnc,
                                                         GdaVConnectionDataModelFunc func,
                                                         gpointer data);

Call func for each GdaDataModel represented as a table in cnc.

cnc : a GdaVconnectionDataModel connection
func : a GdaVConnectionDataModelFunc function pointer
data : data to pass to cunc calls

See Also

The GdaVproviderDataModel provider to use to create such connection objects.



[2] As virtual connections are implemented using SQLite's virtual table features, the SQL dialect which can be used is the SQLite one (see the SQL as Understood By SQLite page), and there are a few limitations inherent to this implementation (see link for more information).

Also note that it is possible to create temporary tables in virtual connections using "CREATE TEMP TABLE..." statements, but the contents of such tables will be lost once the connection is closed.