Hi Jim,

coming to this, is there an easy way to implement deactivation of
constraints? I believe (haven't looked into the source of FB) that (almost)
all constraints are enforced by triggers, right?

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"Jim Starkey" <jas@...> wrote in message
news:3.0.5.32.20011015165349.00b6ee70@......

> While I'm in the area, I thought I'd share a solution to the
> problem of programatic activation/deactivation of triggers.
>
> Netfrastructure has a trigger happy customer who desired
> to deactivate selected triggers during certain system management
> operations but without taking the database generally off line.
> The Interbase DDL to set triggers inactive was too crude a
> tool since that would affect all users, not just his system
> administration procedures. I came up with a simple, elegant
> (well, I think so), lightweight solution that seems to answer
> nicely.
>
> The mechanism consists of another clause on trigger definitions
> ( class <trigger_class_name> ) and two two DDL systems
> "enable <trigger_class_name>" and "disable <trigger_class_name>".
> Yes, a trigger may be a member of an arbitrary number of classes.
>
> The disable statement disables triggers of the given name for
> either the duration of connection or until the trigger class
> is explicitly enabled with the enable trigger class statement.
>
> Trigger classes are not explicitly declared, just used.
>
> The implementation is dirt cheap. The attachment object keeps
> a list of disabled class names. Before a prospective trigger
> fires, it loops through the set of disabled classes to see
> if it has been turned off.
>
> Jim Starkey
>
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