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Posted by --CELKO-- on 10/01/89 11:40
Please post DDL, so that people do not have to guess what the keys,
constraints, Declarative Referential Integrity, data types, etc. in
your schema are. Sample data is also a good idea, along with clear
specifications.
Your design sounds flawed. You have a customer_id which has a huge
size, and no way to validate it (check digit, anything??) Next, we
seldom use binary flags in SQL; instead we have a history with (start,
finish, status) triplets and/or an encodeing scheme for the status.
When I see a table named "CHECKED", I get scared. That is a status,
not an entity or relationship!! It means that you have split an
attribute out of an entity and made it into a separate table. If you
had a "MalePersonnel" and a "FemalePersonnel", you see the flaw of a
split on "sex" immediately.
Knowing that uppercase names are almost 10 times more often mis-read or
mis-typed, why did you use them? We had no choice in the days of
punchcards. In fact, you whoel design seems to be a punch card system
done in SQL.
You need to learn BASIC RDBMS, and how to use VIEWs.
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