Jan, > Because the value in b.y is redundant. b.x->a.x->a.y is exactly the same > value and he even wants to ensure this with the constraint.
And in the absence of that constraint, what ensures that b.y = a.y, exactly? -- Josh Berkus Aglio Database Solutions San Francisco ---------------------------(end of broadcast)--------------------------- TIP 3: if posting/reading through Usenet, please send an appropriate subscribe-nomail command to [EMAIL PROTECTED] so that your message can get through to the mailing list cleanly