Re: Entity Overlap and Relationships
Date: 20 Apr 2006 05:37:49 -0700
Message-ID: <1145536669.780802.36540_at_g10g2000cwb.googlegroups.com>
GB wrote:
> Thanks dawn! That is exactly what I was thinking of doing. Is that a
> bad solution to have an EntityID as a foreign key in an address table
> that could be linked to an EntityID (primary key) in multiple tables?
> Thanks again! GB
That would be a bad design in a SQL-DBMS. It would be redundant since the information about the link between tables would be in each of the separate Entity1-3 tables, pointing to the Address. Additionally, a single address could be pointed to from multiple places (there is likely no reason to make that impossible), which would make this foreign key in your Address file have multiple values.
The use of redundant "return links" is an accepted design in some non-relational databases, particularly those that permit multiple values for an attribute.
HTH. --dawn Received on Thu Apr 20 2006 - 14:37:49 CEST