Event Trigger Dialog v8
Use the Domain Trigger
dialog to define an event trigger. Unlike regular triggers, which are attached to a single table and capture only DML events, event triggers are global to a particular database and are capable of capturing DDL events. Like regular triggers, event triggers can be written in any procedural language that includes event trigger support, or in C, but not in SQL.
The Domain Trigger
dialog organizes the development of a event trigger through the following dialog tabs: General
, Definition
, and Security Labels
. The SQL
tab displays the SQL code generated by dialog selections.
Use the fields in the General
tab to identify the event trigger:
- Use the
Name
field to add a descriptive name for the event trigger. The name will be displayed in theBrowser
tree control. - Use the drop-down listbox next to
Owner
to specify the owner of the event trigger. - Store notes about the event trigger in the
Comment
field.
Click the Definition
tab to continue.
Use the fields in the Definition
tab to define the event trigger:
- Select a value from the drop down of
Trigger Enabled
field to specify a status Select a value from the drop down ofTrigger Enabled
field to specify a status - Use the drop-down listbox next to
Trigger function
to specify an existing function. A trigger function takes an empty argument list, and returns a value of type event_trigger. - Select a value from the drop down of
Events
field to specify when the event trigger will fire:DDL COMMAND START
,DDL COMMAND END
, orSQL DROP
. - Use the
When TAG in
field to enter filter values for TAG for which the trigger will be executed. The values must be in single quotes separated by comma.
Click the Security Labels
tab to continue.
Use the Security
tab to define security labels applied to the trigger. Click the Add
icon (+) to add each security label.
- Specify a security label provider in the
Provider
field. The named provider must be loaded and must consent to the proposed labeling operation. - Specify a security label in the
Security Label
field. The meaning of a given label is at the discretion of the label provider. PostgreSQL places no restrictions on whether or how a label provider must interpret security labels; it merely provides a mechanism for storing them.
Click the Add
icon (+) to assign additional security labels; to discard a security label, click the trash icon to the left of the row and confirm deletion in the Delete Row
popup.
Click the SQL
tab to continue.
Your entries in the Domain Trigger
dialog generate a generate a SQL command. Use the SQL
tab for review; revisit or switch tabs to make any changes to the SQL command.
Example
The following is an example of the sql command generated by user selections in the Domain Trigger
dialog:
The command creates an event trigger named accounts
that invokes the procedure named acct_due
.
- Click the
Info
button (i) to access online help. View context-sensitive help in theTabbed browser
, where a new tab displays the PostgreSQL core documentation. - Click the
Save
button to save work. - Click the
Cancel
button to exit without saving work. - Click the
Reset
button to restore configuration parameters.