52.56. pg_trigger

The catalog pg_trigger stores triggers on tables and views. See CREATE TRIGGER for more information.

Table 52.56. pg_trigger Columns

Column Type Description
oid oid Row identifier
tgrelid oid (references pg_class.oid) The table this trigger is on
tgparentid oid (references pg_trigger.oid) Parent trigger that this trigger is cloned from (this happens when partitions are created or attached to a partitioned table); zero if not a clone
tgname name Trigger name (must be unique among triggers of same table)
tgfoid oid (references pg_proc.oid) The function to be called
tgtype int2 Bit mask identifying trigger firing conditions
tgenabled char Controls in which session_replication_role modes the trigger fires. O = trigger fires in “origin” and “local” modes, D = trigger is disabled, R = trigger fires in “replica” mode, A = trigger fires always.
tgisinternal bool True if trigger is internally generated (usually, to enforce the constraint identified by tgconstraint)
tgconstrrelid oid (references pg_class.oid) The table referenced by a referential integrity constraint (zero if trigger is not for a referential integrity constraint)
tgconstrindid oid (references pg_class.oid) The index supporting a unique, primary key, referential integrity, or exclusion constraint (zero if trigger is not for one of these types of constraint)
tgconstraint oid (references pg_constraint.oid) The pg_constraint entry associated with the trigger (zero if trigger is not for a constraint)
tgdeferrable bool True if constraint trigger is deferrable
tginitdeferred bool True if constraint trigger is initially deferred
tgnargs int2 Number of argument strings passed to trigger function
tgattr int2vector (references pg_attribute.attnum) Column numbers, if trigger is column-specific; otherwise an empty array
tgargs bytea Argument strings to pass to trigger, each NULL-terminated
tgqual pg_node_tree Expression tree (in nodeToString() representation) for the trigger's WHEN condition, or null if none
tgoldtable name REFERENCING clause name for OLD TABLE, or null if none
tgnewtable name REFERENCING clause name for NEW TABLE, or null if none

Currently, column-specific triggering is supported only for UPDATE events, and so tgattr is relevant only for that event type. tgtype might contain bits for other event types as well, but those are presumed to be table-wide regardless of what is in tgattr.

Note

When tgconstraint is nonzero, tgconstrrelid, tgconstrindid, tgdeferrable, and tginitdeferred are largely redundant with the referenced pg_constraint entry. However, it is possible for a non-deferrable trigger to be associated with a deferrable constraint: foreign key constraints can have some deferrable and some non-deferrable triggers.

Note

pg_class.relhastriggers must be true if a relation has any triggers in this catalog.