DML Triggers

Data Manipulation (DML) StatementsBuilt-in Scalar Functions

DML Triggers

DML triggers are those that fire when a DML operation changes the state of data: updating rows in tables, inserting new rows or deleting rows.They can be defined for both tables and views.

Trigger Options

Six base options are available for the event-phase combination for tables and views:

Before a new row is inserted

BEFORE INSERT

After a new row is inserted

AFTER INSERT

Before a row is updated

BEFORE UPDATE

After a row is updated

AFTER UPDATE

Before a row is deleted

BEFORE DELETE

After a row is deleted

AFTER DELETE

These base forms are for creating single phase/single-event triggers.Firebird also supports forms for creating triggers for one phase and multiple-events, BEFORE INSERT OR UPDATE OR DELETE, for example, or AFTER UPDATE OR DELETE: the combinations are your choice.

Note	“Multi-phase” triggers, such as `BEFORE OR AFTER …`, are not possible.

The Boolean context variables INSERTING, UPDATING and DELETING can be used in the body of a trigger to determine the type of event that fired the trigger.