PostgreSQL: tables without PK

Source: http://petereisentraut.blogspot.fr/2009/07/how-to-find-all-tables-without-primary.html

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-- Tables of db2 without PK SELECT table_catalog, table_schema, table_name     FROM information_schema.tables     WHERE (table_catalog, table_schema, table_name) NOT IN           (SELECT table_catalog, table_schema, table_name                FROM information_schema.table_constraints                WHERE constraint_type = 'PRIMARY KEY')       AND table_schema NOT IN ('information_schema', 'pg_catalog') and table_schema ~ '_db$' and table_schema not in ('prov_db', 'queue_db', 'ota_db', 'sla_db');