PostgreSQL 8.5alpha3 Documentation | ||||
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The catalog pg_trigger stores triggers on tables. See CREATE TRIGGER for more information.
Table 44-39. pg_trigger Columns
Name | Type | References | Description |
---|---|---|---|
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 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. | |
tgisconstraint | bool | True if trigger is a "constraint trigger" | |
tgconstrname | name | Constraint name, if a constraint trigger | |
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, or referential integrity constraint |
tgconstraint | oid | pg_constraint.oid | The pg_constraint entry owning 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 | text | Expression tree (in nodeToString()
representation) for the trigger's WHEN condition, 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, tgisconstraint must be true, and tgconstrname, tgconstrrelid, tgconstrindid, tgdeferrable, tginitdeferred are redundant with the referenced pg_constraint entry. The reason we keep these fields is that we support "stand-alone" constraint triggers with no corresponding pg_constraint entry.
Note: pg_class.relhastriggers must be true if a table has any triggers in this catalog.