---
title: "pg_trigger"
id: catalog-pg-trigger
pg_version: "20devel"
---

<a id="catalog-pg-trigger"></a>

## 52.63. pg_trigger

The catalog pg_trigger stores triggers on tables and views. See [CREATE TRIGGER](sql-createtrigger.md) for more information. 

**pg_trigger Columns**

| Column Type | Description | 
| --- | --- |
| `oid` `oid` | Row identifier |
| `tgrelid` `oid` (references [pg_class](catalog-pg-class.md).`oid`) | The table this trigger is on |
| `tgparentid` `oid` (references [pg_trigger](catalog-pg-trigger.md).`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](catalog-pg-proc.md).`oid`) | The function to be called |
| `tgtype` `int2` | Bit mask identifying trigger firing conditions |
| `tgenabled` `char` | Controls in which [`session_replication_role` (`enum`)](runtime-config-client.md#guc-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](catalog-pg-class.md).`oid`) | The table referenced by a referential integrity constraint (zero if trigger is not for a referential integrity constraint) |
| `tgconstrindid` `oid` (references [pg_class](catalog-pg-class.md).`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](catalog-pg-constraint.md).`oid`) | The [pg_constraint](catalog-pg-constraint.md) 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](catalog-pg-attribute.md).`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](catalog-pg-constraint.md) 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.