Overview

The MySQL mode of OceanBase Database is compatible with the triggers of MySQL 5.6. Triggers are database objects that are associated with tables and are activated when specific events occur on a table.

To be specific, a trigger can be activated when a row is inserted into, updated in, or deleted from an associated table by using a statement. For example, you can activate an INSERT trigger for each row inserted using the INSERT or LOAD DATA statement. If you insert two rows of data in a batch, the trigger will be activated twice.

Triggers can be set to activate before or after a triggering event. For example, you can activate a trigger before each row is inserted into the table or after each row is updated.

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

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

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

• DELETE: A trigger of this type is activated 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 is activated 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.