21.27 The INFORMATION_SCHEMA TRIGGERS Table

The TRIGGERS table provides information about triggers. To see information about a table's triggers, you must have the TRIGGER privilege for the table.

The TRIGGERS table has these columns:

TRIGGER_CATALOG
The name of the catalog to which the trigger belongs. This value is always def.
TRIGGER_SCHEMA
The name of the schema (database) to which the trigger belongs.
TRIGGER_NAME
The name of the trigger.
EVENT_MANIPULATION
The trigger event. This is the type of operation on the associated table for which the trigger activates. The value is INSERT (a row was inserted), DELETE (a row was deleted), or UPDATE (a row was modified).
EVENT_OBJECT_CATALOG, EVENT_OBJECT_SCHEMA, and EVENT_OBJECT_TABLE
As noted in Section 20.3, “Using Triggers”, every trigger is associated with exactly one table. These columns indicate the catalog and schema (database) in which this table occurs, and the table name, respectively. The EVENT_OBJECT_CATALOG value is always def.
ACTION_ORDER
The ordinal position of the trigger's action within the list of all similar triggers on the same table. This value is always 0 because it is not possible to have more than one trigger with the same EVENT_MANIPULATION and ACTION_TIMING on the same table.
ACTION_CONDITION
This value is always NULL.
ACTION_STATEMENT
The trigger body; that is, the statement executed when the trigger activates. This text uses UTF-8 encoding.
ACTION_ORIENTATION
This value is always ROW.
ACTION_TIMING
Whether the trigger activates before or after the triggering event. The value is BEFORE or AFTER.
ACTION_REFERENCE_OLD_TABLE
This value is always NULL.
ACTION_REFERENCE_NEW_TABLE
This value is always NULL.
ACTION_REFERENCE_OLD_ROW and ACTION_REFERENCE_NEW_ROW
The old and new column identifiers, respectively. The ACTION_REFERENCE_OLD_ROW value is always OLD and the ACTION_REFERENCE_NEW_ROW value is always NEW.
CREATED
This value is always NULL.
SQL_MODE
The SQL mode in effect when the trigger was created, and under which the trigger executes. For the permitted values, see Section 5.1.10, “Server SQL Modes”.
DEFINER
The account named in the DEFINER clause (often the user who created the trigger), in 'user_name'@'host_name' format.
CHARACTER_SET_CLIENT
The session value of the character_set_client system variable when the trigger was created.
COLLATION_CONNECTION
The session value of the collation_connection system variable when the trigger was created.
DATABASE_COLLATION
The collation of the database with which the trigger is associated.

Example

The following example uses the ins_sum trigger defined in Section 20.3, “Using Triggers”:

mysql> SELECT * FROM INFORMATION_SCHEMA.TRIGGERS
       WHERE TRIGGER_SCHEMA='test' AND TRIGGER_NAME='ins_sum'\G
*************************** 1. row ***************************
           TRIGGER_CATALOG: def
            TRIGGER_SCHEMA: test
              TRIGGER_NAME: ins_sum
        EVENT_MANIPULATION: INSERT
      EVENT_OBJECT_CATALOG: def
       EVENT_OBJECT_SCHEMA: test
        EVENT_OBJECT_TABLE: account
              ACTION_ORDER: 0
          ACTION_CONDITION: NULL
          ACTION_STATEMENT: SET @sum = @sum + NEW.amount
        ACTION_ORIENTATION: ROW
             ACTION_TIMING: BEFORE
ACTION_REFERENCE_OLD_TABLE: NULL
ACTION_REFERENCE_NEW_TABLE: NULL
  ACTION_REFERENCE_OLD_ROW: OLD
  ACTION_REFERENCE_NEW_ROW: NEW
                   CREATED: NULL
                  SQL_MODE: NO_ENGINE_SUBSTITUTION
                   DEFINER: me@localhost
      CHARACTER_SET_CLIENT: utf8
      COLLATION_CONNECTION: utf8_general_ci
        DATABASE_COLLATION: latin1_swedish_ci

Trigger information is also available from the SHOW TRIGGERS statement. See Section 13.7.5.39, “SHOW TRIGGERS Statement”.