INFORMATION_SCHEMA TRIGGERS

The INFORMATION_SCHEMA TRIGGERS dictionary view provides information about triggers. To view information about triggers on a table, you must have the TRIGGER privilege on the table.

The INFORMATION_SCHEMA TRIGGERS dictionary view contains the following fields:

Field Name	Description
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 trigger name.
EVENT_MANIPULATION	The trigger event. This is the type of operation that activates the trigger on the associated table. The value can be INSERT (a row is inserted), DELETE (a row is deleted), or UPDATE (a row is modified).
EVENT_OBJECT_CATALOG、EVENT_OBJECT_SCHEMA、 EVENT_OBJECT_TABLE	Each trigger is associated with one table. These fields respectively indicate the catalog and schema (database) in which the table is located, as well as the table name. The value of EVENT_OBJECT_CATALOG is always def.
ACTION_ORDER	The order and position of the trigger operation in the list of triggers on the same table with the same EVENT_MANIPULATION and ACTION_TIMING values.
ACTION_CONDITION	This value is always NULL.
ACTION_STATEMENT	The statement executed when the trigger is activated. The text is encoded in UTF-8.
ACTION_ORIENTATION	This value is always ROW .
ACTION_TIMING	Whether the trigger is activated before or after the trigger event. The value can be 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、ACTION_REFERENCE_NEW_ROW	The identifiers of the old and new columns. The value of ACTION_REFERENCE_OLD_ROW is always OLD. The value of ACTION_REFERENCE_NEW_ROW is always NEW.
CREATED	The date and time when the trigger was created. The value is of the TIMESTAMP(2) type, with the fractional part in hundredths of a second.
SQL_MODE	The SQL mode in effect when the trigger was created.
DEFINER	The account specified in the DEFINER clause (usually the user who created the trigger), in the format 'user_name'@'host_name'.
CHARACTER_SET_CLIENT	The value of the character_set_client system variable in the current session when the trigger was created.
COLLATION_CONNECTION	The value of the collation_connection system variable in the current session when the trigger was created.
DATABASE_COLLATION	The collation of the database associated with the trigger.

Here is an example:

SELECT * FROM INFORMATION_SCHEMA.TRIGGERS
       WHERE TRIGGER_SCHEMA='test' AND TRIGGER_NAME='test_trg'\G
*************************** 1. row ***************************
           TRIGGER_CATALOG: def
            TRIGGER_SCHEMA: test
              TRIGGER_NAME: test_trg
        EVENT_MANIPULATION: UPDATE
      EVENT_OBJECT_CATALOG: def
       EVENT_OBJECT_SCHEMA: test
        EVENT_OBJECT_TABLE: test
              ACTION_ORDER: 0
          ACTION_CONDITION: NULL
          ACTION_STATEMENT: TRIGGER test_trg BEFORE UPDATE ON test
                            FOR EACH ROW
                            BEGIN
                            IF NEW.user_num < 1 THEN
                            SET NEW.user_num  = 1;
                            ELSEIF NEW.user_num > 45 THEN
                            SET NEW.user_num= 45;
                            END IF;
                            END
        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: 2022-05-18 18:07:51.994639
                  SQL_MODE: STRICT_ALL_TABLES,NO_ZERO_IN_DATE
                   DEFINER: 'root'@'%'
      CHARACTER_SET_CLIENT: utf8mb4
      COLLATION_CONNECTION: utf8mb4
        DATABASE_COLLATION: utf8mb4