pg_rewrite

The pg_rewrite system catalog table stores rewrite rules for tables and views. pg_class.relhasrules must be true if a table has any rules in this catalog.

column	type	references	description
rulename	name		Rule name.
ev_class	oid	pg_class.oid	The table this rule is for.
ev_attr	int2		The column this rule is for (currently, always zero to indicate the whole table).
ev_type	char		Event type that the rule is for: 1 = SELECT, 2 = UPDATE, 3 = INSERT, 4 = DELETE.
is_instead	boolean		True if the rule is an INSTEAD rule.
ev_qual	text		Expression tree (in the form of a nodeToString() representation) for the rule's qualifying condition.
ev_action	text		Query tree (in the form of a nodeToString() representation) for the rule's action.

Parent topic: System Catalogs Definitions