GLib.Relation¶

Fields¶

None

Methods¶

	`count` (key, field)
	`delete` (key, field)
	`destroy` ()
	`print_` ()

Details¶

class GLib.Relation¶

A GRelation is a table of data which can be indexed on any number of fields, rather like simple database tables. A GRelation contains a number of records, called tuples. Each record contains a number of fields. Records are not ordered, so it is not possible to find the record at a particular index.

Note that GRelation tables are currently limited to 2 fields.

To create a GRelation, use [func`GLib`.Relation.new].

To specify which fields should be indexed, use [method`GLib`.Relation.index]. Note that this must be called before any tuples are added to the GRelation.

To add records to a GRelation use [method`GLib`.Relation.insert].

To determine if a given record appears in a GRelation, use [method`GLib`.Relation.exists]. Note that fields are compared directly, so pointers must point to the exact same position (i.e. different copies of the same string will not match.)

To count the number of records which have a particular value in a given field, use [method`GLib`.Relation.count].

To get all the records which have a particular value in a given field, use [method`GLib`.Relation.select]. To access fields of the resulting records, use [method`GLib`.Tuples.index]. To free the resulting records use [method`GLib`.Tuples.destroy].

To delete all records which have a particular value in a given field, use [method`GLib`.Relation.delete].

To destroy the GRelation, use [method`GLib`.Relation.destroy].

To help debug GRelation objects, use [method`GLib`.Relation.print].

GRelation has been marked as deprecated, since this API has never been fully implemented, is not very actively maintained and rarely used.

Deprecated since version 2.26: Rarely used API

count(key, field)[source]¶

Parameters:

key (object or None) – the value to compare with.
field (int) – the field of each record to match.

Returns:

the number of matches.

Return type:

int

Returns the number of tuples in a GLib.Relation that have the given value in the given field.

Deprecated since version 2.26: Rarely used API

delete(key, field)[source]¶

Parameters:

key (object or None) – the value to compare with.
field (int) – the field of each record to match.

Returns:

the number of records deleted.

Return type:

int

Deletes any records from a GLib.Relation that have the given key value in the given field.

Deprecated since version 2.26: Rarely used API

destroy()[source]¶: Destroys the GLib.Relation, freeing all memory allocated. However, it does not free memory allocated for the tuple data, so you should free that first if appropriate.

Deprecated since version 2.26: Rarely used API

print_()[source]¶: Outputs information about all records in a GLib.Relation, as well as the indexes. It is for debugging.

Deprecated since version 2.26: Rarely used API