The catalog pg_trigger stores triggers on tables and views. See CREATE TRIGGER for more information.
Table 51.56. pg_trigger Columns
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.
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.
pg_class.relhastriggers must be true if a relation has any triggers in this catalog.
Name
Type
References
Description
oid
oid
Row identifier (hidden attribute; must be explicitly selected)
tgrelid
oid
pg_class.oid
The table this trigger is on
tgname
name
Trigger name (must be unique among triggers of same table)
tgfoid
oid
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
pg_class.oid
The table referenced by a referential integrity constraint
tgconstrindid
oid
pg_class.oid
The index supporting a unique, primary key, referential integrity, or exclusion constraint
tgconstraint
oid
pg_constraint.oid
The pg_constraint entry associated with the trigger, if any
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
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