>>Could they be FK to some tables?
>
>The meaning of FKs is NOT TO HAVE orphan records :-)
What if you don't necessary require an entry for the ID? E.g. you may have a Key, then it should be in the child table, but you also allow to not have a relation.
In our case (though VFP native tables) we used NULL in FK for such cases.
If it's not broken, fix it until it is.
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