pgadmin4/docs/en_US/rule_dialog.rst
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.. _rule_dialog:
********************
`Rule Dialog`:index:
********************
Use the *Rule* dialog to define or modify a rule for a specified table or view.
A PostgreSQL rule allows you to define an additional action that will be
performed when a SELECT, INSERT, UPDATE, or DELETE is performed against a table.
The *Rule* dialog organizes the development of a rule through the *General*,
and *Definition* tabs. The *SQL* tab displays the SQL code generated by dialog
selections.
.. image:: images/rule_general.png
:alt: Rule dialog general tab
:align: center
Use the fields in the *General* tab to identify the rule:
* Use the *Name* field to add a descriptive name for the rule. The name will be
displayed in the *pgAdmin* tree control. Multiple rules on the same table are
applied in alphabetical name order.
* Store notes about the rule in the *Comment* field.
Click the *Definition* tab to continue.
.. image:: images/rule_definition.png
:alt: Rule dialog definition tab
:align: center
Use the fields in the *Definition* tab to write parameters:
* Click inside the *Event* field to select the type of event that will invoke
the rule; event may be *Select*, *Insert*, *Update*, or *Delete*.
* Move the *Do Instead* switch to *Yes* indicate that the commands should be
executed instead of the original command; if Do Instead specifies *No*, the
rule will be invoked in addition to the original command.
* Specify a SQL conditional expression that returns a boolean value in the
*Condition* editor.
* Provide a command in the *Commands* editor that defines the action performed
by the rule.
Click the *SQL* tab to continue.
Your entries in the *Rule* dialog generate a SQL command (see an example below).
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 *Rule* dialog:
.. image:: images/rule_sql.png
:alt: Rule dialog sql tab
:align: center
The example sends a notification when an UPDATE executes against a table.
* Click the *Info* button (i) to access online help.
* Click the *Save* button to save work.
* Click the *Cancel* button to exit without saving work.
* Click the *Reset* button to restore configuration parameters.