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From MZ_TRICSTA <mz_tric...@yahoo.com>
Subject RE: Determine which child table a record belongs to
Date Tue, 29 Jan 2008 18:04:26 GMT

Thanks for your help, Brad. You are absolutely right. In this case, it
doesn't make sense to have so many tables. I will make the changes you
suggest. However, there are times when it does make sense to have this kind
of hierarchical structure such as when the child tables have different
fields, so my question remains: How would I determine which of the child
tables the key belongs to without querying each child table? I appreciate
any further assistance.

Again Thanks,

Brad Moore wrote:
> Can I suggest changing the "Crane" table to include a CraneType column or
> something similar?  I don't know if there is a reason that's not obvious
> to me why you need all of the other tables.  It looks like you're using
> the other tables to determine the type of crane, the same thing could be
> done with one additional column in the Crane table.  That would simplify
> your database design a lot.  Unless I'm missing something.
> Brad

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