ALTER EVENT statement

Changes the definition of an event or its associated handler for automating predefined actions, or alters the definition of scheduled actions. You can also use this statement to hide the definition of an event handler.

Syntax 1 - Altering an event

ALTER EVENT [ owner.]event-name 
[ AT { CONSOLIDATED | REMOTE | ALL } ]
[ FOR { PRIMARY | ALL} ]
[ { DELETE TYPE 
   | TYPE event-type 
   | WHERE { trigger-condition | NULL }
   | { ADD | ALTER | DELETE } SCHEDULE schedule-spec } ]
[ ENABLE | DISABLE ]
[ [ ALTER ] HANDLER compound-statement | DELETE HANDLER ]

event-type :
BackupEnd 
| Connect 
| ConnectFailed 
| DatabaseStart
| DBDiskSpace
| Deadlock 
| "Disconnect" 
| GlobalAutoincrement 
| GrowDB
| GrowLog 
| GrowTemp
| LogDiskSpace 
| RAISERROR
| ServerIdle 
| TempDiskSpace

trigger-condition :
event_condition( condition-name ) { = | < | > | != | <= | >= } value

schedule-spec :
[ schedule-name ]
   { START TIME start-time | BETWEEN start-time AND end-time }
   [ EVERY period { HOURS | MINUTES | SECONDS } ]
   [ ON { ( day-of-week, ... ) | ( day-of-month, ... ) } ]
   [ START DATE start-date ]

event-name | schedule-name :  identifier

day-of-week :  string

value | period | day-of-month :  integer

start-time | end-time : time

start-date : date

Syntax 2 - Hiding the definition of an event handler

ALTER EVENT event-name SET HIDDEN

Parameters

AT clause Use this clause to change the specification regarding the databases at which the event is handled.
FOR clause Use this clause in a database mirroring or read-only scale-out system to restrict the databases at which the event is handled.
DELETE TYPE clause Use this clause to remove an association of the event with an event type.
ADD | ALTER | DELETE SCHEDULE clause Use this clause to change the definition of a schedule. Only one schedule can be altered in any one ALTER EVENT statement.
WHERE clause Use this clause to change the trigger condition under which an event is fired. The WHERE NULL option deletes a condition.
START TIME clause Use this clause to specify the start time and, optionally, the end time, for the event. The start-time and end-time parameters are strings (for example, '12:34:56'). Variables and expressions are not allowed (for example, NOW()).
START DATE clause Use this clause to specify the start date for the event. The start-date parameter is a string. Variables and expressions are not allowed (for example, TODAY()).
SET HIDDEN clause Use this clause to hide the definition of an event handler. Specifying the SET HIDDEN clause results in the permanent obfuscation of the event handler definition stored in the action column of the ISYSEVENT system table.

Remarks

This statement allows you to alter an event definition created with CREATE EVENT. Possible uses include the following:

hiding the definition of an event handler
defining and testing an event handler without a trigger condition or schedule during a development phase, and then adding the conditions for execution using ALTER EVENT once the event handler is completed

If you need to alter an event, you can disable it while it is running by executing an ALTER EVENT...DISABLE statement. To disable an event in Sybase Central, right-click the event and clear the Enabled option. Disabling the event does not interrupt current event handler execution; the event handler continues to execute until completion. When the event handler completes, it is not restarted until you re-enable it. You can alter and then re-enable the definition. To determine what events are running, execute the following statement:

SELECT * 
FROM dbo.sa_conn_info()
WHERE CONNECTION_PROPERTY( 'EventName',Number ) = 'event-name';