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  1. Using Expressions and Properties in Constraints

    by , 14-Aug-2009 at 08:00 AM (Development Team Blog)
    In Sonny Falkís blog about constraints and local variables he noted that you should never use local variables inside of a Constrain As expression. In talking about Constrain As he states:
    You constrain against an expression, and the expression can be anything at all, including function calls executing DataFlex code and everything.
    Letís explore the use of Constrain As to call DataFlex functions and uncover one of the little secrets of inherited constraints.

    Constraints and User ...

    Updated 14-Aug-2009 at 08:36 AM by Stephen W. Meeley (Minor formatting.)

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  2. Constraints and Local Variables

    by , 10-Aug-2009 at 07:00 AM (Development Team Blog)
    Constraints and local variables is a frequent question in the forums, let's see if we can sort this out. The basics is that you set it up once, and then the runtime uses the constraints when finding records thereafter. If you want to change your constraints, you rebuild the whole set of constraints, and then the runtime uses that thereafter.

    The way constraints are set up is complicated a little with DDs and I won't go into the details, but essentially you augment the [I]OnConstrain[/I] ...