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Posted by David Portas on 12/07/05 19:19
Mike wrote:
> Can anyone tell me what is best practices to define relationships between
> tables and to define their primary key?
>
I think you mean Foreign Keys, not "relationships". Foreign Keys
maintain referential integrity by ensuring that data is complete and
consistent in your tables.
> For example...
> One table is Orders and other is OrderDetails.
> For ease of accessing datas from table OrderDetails I have fields copied
> from Orders like year_of_order, order_number, client_id.
>
What does "ease of accessing data" mean? I think you are making a
fundamental error. Do you understand what Normalization is? There is a
set of well-founded principles for designing a database schema and you
don't seem to be familiar with them. I recommend you take a course or
study a book on design because there is far more material for you to
cover than we can sensibly try to convey in a newsgroup.
--
David Portas
SQL Server MVP
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