pg_trigger
The catalog pg_trigger stores triggers on tables
and views.
See CREATE TRIGGER
for more information.
Table 51.57. pg_trigger Columns
| Name | Type | References | Description |
|---|---|---|---|
oid | oid | Row identifier | |
tgrelid | oid | | The table this trigger is on |
tgname | name | Trigger name (must be unique among triggers of same table) | |
tgfoid | 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 | | The table referenced by a referential integrity constraint |
tgconstrindid | oid | | The index supporting a unique, primary key, referential integrity, or exclusion constraint |
tgconstraint | 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 | | 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.
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.