CHANGE()

BeforeModifyView, AfterModifyView

These database events fire when a view is modified in the View Designer.

Usage

PROCEDURE DBC_BeforeModifyView( cViewName )   PROCEDURE DBC_AfterModifyView( cViewName, lChanged )

Parameter	Value	Meaning
cViewName	Character	The name of the view being modified.
lChanged	Logical	Indicates whether the view was changed.

Like other before-and-after pairs of events, you can prevent a view from being modified (the View Designer won't appear) by returning .F. in the BeforeModifyView event, while the AfterModifyView event simply fires, notifying you that the view was modified and either changed or not.

As discussed in the "Database Events" topic, there's no way to tell what changes a user made, so if that's important, you'll have to save the current view structure in the BeforeModifyView event, or rely on metadata that saves that information somewhere, and then compare the saved information against the view structure in the AfterModifyView event.

Example

* This goes in the stored procedures of a database.   PROCEDURE DBC_BeforeModifyView(cViewName) WAIT WINDOW PROGRAM() + CHR(13) + ;     'cViewName: ' + cViewName   PROCEDURE DBC_AfterModifyView(cViewName, lChanged) WAIT WINDOW PROGRAM() + CHR(13) + ;     'cViewName: ' + cViewName + CHR(13) + ;     'lChanged: ' + TRANSFORM(lChanged)   * End of stored procedures.     * Create a view, and then modify it.   OPEN DATABASE TestData DBSETPROP(DBC(), 'Database', 'DBCEvents', .T.) && Turn on events CREATE SQL VIEW TestView AS SELECT * FROM Customer MODIFY VIEW TestView

See Also

BeforeCreateView, BeforeDropView, Create SQL View, Database Events, Modify View

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Copyright © 2002 by Tamar E. Granor, Ted Roche, Doug Hennig, and Della Martin. All Rights Reserved.