app/django/db/backends/postgresql_psycopg2/introspection.py
author Daniel Hans <Daniel.M.Hans@gmail.com>
Tue, 03 Nov 2009 00:50:23 +0100
changeset 3075 1e78db95e38a
parent 323 ff1a9aa48cfd
permissions -rw-r--r--
getListContentForData function added to lists helper. It allows to manually set a list of entities which is to be displayed on the view. Previously, the only function was getListContent, but it retrived data on its own by a single query. The new function can be useful whenever it is impossible or very awkward to obtain entities in such a way (for example more sophisticated SQL statements). Additionally, the getListContent function is reconstructed so that it collects the data first and then calls getListContentForData.

from django.db.backends.postgresql.introspection import DatabaseIntrospection as PostgresDatabaseIntrospection

class DatabaseIntrospection(PostgresDatabaseIntrospection):

    def get_relations(self, cursor, table_name):
        """
        Returns a dictionary of {field_index: (field_index_other_table, other_table)}
        representing all relationships to the given table. Indexes are 0-based.
        """
        cursor.execute("""
            SELECT con.conkey, con.confkey, c2.relname
            FROM pg_constraint con, pg_class c1, pg_class c2
            WHERE c1.oid = con.conrelid
                AND c2.oid = con.confrelid
                AND c1.relname = %s
                AND con.contype = 'f'""", [table_name])
        relations = {}
        for row in cursor.fetchall():
            # row[0] and row[1] are single-item lists, so grab the single item.
            relations[row[0][0] - 1] = (row[1][0] - 1, row[2])
        return relations