Zoltan Boszormenyi <[EMAIL PROTECTED]> writes:
> I have two questions about the dependency system.
> 1. Is there a built-in defense to avoid circular dependencies?
It doesn't have a problem with them, if that's what you mean.
> 2. If I register dependencies between column, is there a way
> to retrieve all table/column type dependencies for a depender column?
You can scan pg_depend.
> What I would like to achieve is to lift the limit that
> a GENERATED column cannot reference another one.
I would counsel not doing that, mainly because then you will have to
solve an evaluation-order problem at runtime.
> Point taken. So, just like with SET / DROP IDENTITY,
> I should implement SET GENERATED ALWAYS
> and DROP GENERATED.
If you think of it as a property of the default expression, then DROP
DEFAULT covers both cases, you don't need DROP GENERATED...
regards, tom lane
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TIP 9: In versions below 8.0, the planner will ignore your desire to
choose an index scan if your joining column's datatypes do not
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