Overview

OceanBase Database in MySQL mode is compatible with the triggers of MySQL 5.6. Triggers are database objects that are related to tables. A trigger fires when a particular event occurs on a table.

To be specific, a trigger fires when a row is inserted into, updated in, or deleted from an associated table by using a statement. For example, you can insert rows by using the INSERT or LOAD DATA statement. The INSERT trigger fires each time a row is inserted. If you insert two rows at the same time, the trigger fires twice.

You can specify whether a trigger fires before or after a triggering event. For example, you can specify that a trigger fires before a row is inserted into a table or after a row in the table is updated.

OceanBase Database in MySQL mode supports the following types of triggers:

• INSERT: A trigger of this type fires when you insert a row by using an INSERT, LOAD DATA, or REPLACE statement.

• UPDATE: A trigger of this type fires when you update a row by using an UPDATE statement.

• DELETE: A trigger of this type fires when you delete a row by using a DELETE or REPLACE statement.

The INSERT INTO ... ON DUPLICATE KEY UPDATE statement is a special case in which a BEFORE INSERT trigger fires for each row, followed by an AFTER INSERT trigger or both the BEFORE UPDATE and AFTER UPDATE triggers, based on whether the row has a duplicate key.