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Triggers

DML (data manipulation language) triggers on tables can be created in the AMT Developer Studio from the 'Triggers' node available in Database Table objects.

Triggers can only be used in combination with the Reorganization program, not the older reo program.

Creating a trigger

To create a new trigger, do the following:

• Open the table definition on which you want to define the trigger and select the "Triggers" node.
• Ensure that the table is locked by selecting the lock button in the top toolbar.
• Select the option "Add new trigger" from the right-hand pane. The following screen appears:
  
• To complete the specification, see "Adjusting a trigger" below.

Adjusting a trigger

• Select the trigger you want to adjust from the "Triggers" node.
• Ensure that the table is locked by selecting the lock button in the top toolbar.
• Set the properties for the trigger as described below:

Option:	Description:	Value:
Name	Name of the trigger.	<Text>
Description	Description of the trigger.	<Text>
DML action	Select the DML action(s) that executes the trigger. Multiple actions can be selected if supported by the database type used in your runtime environment.	<Insert|Update|Delete>
Execute after DML	If checked, the trigger will execute after the DML action has been performed. If not checked, the trigger will execute before the DML action.
DB2 - Execute per row - Execute per statement	For DB2 databases only: The trigger will can be executed once for each row in a transaction, or executed once for each transaction/statement. Please note that this option is dependent on which type of database is used in your runtime environment: MsSql: will always execute per statement. Oracle: will always execute per row. DB2: can use either option.

• The trigger SQL code can be set in one of the code nodes belonging to the correct database type, see the code help page for more information.
• On completion, click the save button in the top toolbar of the Developer.
• The table must be checked in first before it can be generated.

Deleting a trigger

• Open the table definition on which you want to adjust the trigger and select the "Triggers" node.
• Ensure that the table is locked by selecting the lock button in the top toolbar.
• Select the trigger to delete and right-click on it, then select "Delete" from the pop-up menu (or press Delete on the keyboard).
• On completion, click the save button in the top toolbar of the Developer.
• The table must be checked in first before it can be generated.

Generate the application and reorganize the database

After a trigger is added, adjusted or deleted, a Whole System generate is required, followed by a database reorganize.

Triggers that were manually disabled, will be re-enabled by a database reorganize only when the columns in the triggers have been changed. Unchanged triggers will not be re-enabled by a database reorganize.

In the code nodes, the SQL code of the trigger can be set.