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.
|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.|