mirror of
https://github.com/pgadmin-org/pgadmin4.git
synced 2024-12-26 08:51:49 -06:00
107 lines
4.0 KiB
ReStructuredText
107 lines
4.0 KiB
ReStructuredText
.. _trigger_dialog:
|
|
|
|
***********************
|
|
`Trigger Dialog`:index:
|
|
***********************
|
|
|
|
Use the *Trigger* dialog to create a trigger or modify an existing trigger. A
|
|
trigger executes a specified function when certain events occur.
|
|
|
|
The *Trigger* dialog organizes the development of a trigger through the
|
|
following dialog tabs: *General*, *Definition*, *Events*, and *Code*. The *SQL*
|
|
tab displays the SQL code generated by dialog selections.
|
|
|
|
.. image:: images/trigger_general.png
|
|
:alt: Trigger dialog general tab
|
|
:align: center
|
|
|
|
Use the fields in the *General* tab to identify the trigger:
|
|
|
|
* Use the *Name* field to add a descriptive name for the trigger. This must be
|
|
distinct from the name of any other trigger for the same table. The name will
|
|
be displayed in the *pgAdmin* tree control. Note that if multiple triggers of
|
|
the same kind are defined for the same event, they will be fired in
|
|
alphabetical order by name.
|
|
* Store notes about the trigger in the *Comment* field.
|
|
|
|
Click the *Definition* tab to continue.
|
|
|
|
.. image:: images/trigger_definition.png
|
|
:alt: Trigger dialog definition tab
|
|
:align: center
|
|
|
|
Use the fields in the *Definition* tab to define the trigger:
|
|
|
|
* Move the *Row trigger?* switch to the *No* position to disassociate the
|
|
trigger from firing on each row in a table. The default is *Yes*.
|
|
* Move the *Constraint trigger?* switch to the *Yes* position to specify the
|
|
trigger is a constraint trigger.
|
|
* If enabled, move the *Deferrable?* switch to the *Yes* position to specify
|
|
the timing of the constraint trigger is deferrable and can be postponed until
|
|
the end of the statement. The default is *No*.
|
|
* If enabled, move the *Deferred?* switch to the *Yes* position to specify the
|
|
timing of the constraint trigger is deferred to the end of the statement
|
|
causing the triggering event. The default is *No*.
|
|
* Use the drop-down listbox next to *Trigger Function* to select a trigger
|
|
function or procedure.
|
|
* Use the *Arguments* field to provide an optional (comma-separated) list of
|
|
arguments to the function when the trigger is executed. The arguments are
|
|
literal string constants.
|
|
|
|
.. image:: images/trigger_definition_enabled.png
|
|
:alt: Trigger enabled in dialog tab
|
|
:align: center
|
|
|
|
* *Trigger enabled* field is available in trigger dialog once the trigger is created.
|
|
You can select one of the four options available.
|
|
|
|
Click the *Events* tab to continue.
|
|
|
|
.. image:: images/trigger_events.png
|
|
:alt: Trigger dialog events tab
|
|
:align: center
|
|
|
|
Use the fields in the *Events* tab to specify how and when the trigger fires:
|
|
|
|
* Use the drop-down listbox next to the *Fires* fields to determine if the
|
|
trigger fires *BEFORE* or *AFTER* a specified event. The default is *BEFORE*.
|
|
* Select the type of event(s) that will invoke the trigger; to select an event
|
|
type, move the switch next to the event to the *YES* position. The supported
|
|
event types are *INSERT*, *UPDATE*, *DELETE*, and *TRUNCATE*.
|
|
* Use the *When* field to provide a boolean condition that will invoke the
|
|
trigger.
|
|
* If defining a column-specific trigger, use the *Columns* field to specify the
|
|
columns or columns that are the target of the trigger.
|
|
|
|
Click the *Code* tab to continue.
|
|
|
|
.. image:: images/trigger_code.png
|
|
:alt: Trigger dialog code tab
|
|
:align: center
|
|
|
|
Use the *Code* field to specify any additional code that will be invoked when
|
|
the trigger fires.
|
|
|
|
Click the *SQL* tab to continue.
|
|
|
|
Your entries in the *Trigger* 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 *Trigger* dialog:
|
|
|
|
.. image:: images/trigger_sql.png
|
|
:alt: Trigger dialog sql tab
|
|
:align: center
|
|
|
|
The example demonstrates creating a trigger named *log_update*.
|
|
|
|
* 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.
|