Release 10.1A: OpenEdge Development:
Basic Database Tools

> ## Creating a trigger

> There are two types of triggers: session and schema. You create session triggers as part of a Progress 4GL procedure and create schema triggers using the Data Dictionary. See OpenEdge Development: Progress 4GL Handbook for information about creating session triggers.

> There are two types of schema triggers: table and field.

> | To create a table trigger:

> 1. Choose Schema Add New Table or choose Schema Modify Table. If you are adding a new table, specify a table name. If you are modifying a table, the Data Dictionary alphabetically lists all the tables defined for your database. Select the table for which you want to create the trigger.

> 2. Choose Triggers. The Table Triggers dialog box appears.

> 3. Define the trigger attributes. For more information on the Table Triggers dialog box and the trigger attributes, see the "Table Triggers" section.

> 4. Specify whether a session trigger can override this schema trigger. For more information about session and schema triggers, see the chapter on database triggers in OpenEdge Development: Progress 4GL Handbook .

> 5. Specify whether the database engine checks the cyclical redundancy check (CRC) code for the trigger.

> 6. Press PUT to enter the trigger code. The Data Dictionary displays the Trigger Code dialog box.

> 7. Enter the trigger code.

> 8. Choose OK to return to the Table Triggers dialog box.

> 9. Choose OK to return to the Add Table or Modify Table window.

> | To create a field trigger from an existing field:

> 1. Choose Schema Field Editor. The Field Editor alphabetically lists all the tables defined for your database.

> 2. Select the table that contains the field for which you want to create the trigger. The Field Editor window appears.

> 3. Choose Triggers.

> 4. Select the field for which you want to define the trigger. The Field Triggers dialog box appears:

> 5. Specify the name of the trigger procedure, then press PUT to enter the trigger code. The Trigger Editor appears.

> 6. Specify whether a session trigger can override the schema trigger. For more information about session and schema triggers, see the chapter on database triggers in the OpenEdge Development: Progress 4GL Handbook .

> 7. Specify whether the database engine verifies the cyclical redundancy check (CRC) code.

> 8. Choose OK to create the trigger and return to the Field Editor.

> Note: To generate r-code for schema trigger definitions, you must define the trigger procedure in the Data Dictionary tool, then compile and save the r-code with the Application Compiler.

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