On Apr 27, 2006, at 10:20 AM, Paul Lynch wrote:
On 27 Apr 2006, at 17:47, Chuck Hill wrote:
That does not make any sense in OO or RDBMS terms. Your database
will not allow you to have a FK to two different tables. In OO,
you would not want a relationship to two different classes not in
an inheritance hierarchy. At the very least your code would be
littered with casts and instanceof tests. Ugly.
As a interesting point of fact, I have a customer with a legacy
database that does exactly this, so it is possible.
I should have stated that more clearly. The database can't enforce
the FK in this case. At least I have never seen one that could.
Just because it is ugly (and yes, it is) and doesn't make any
sense, doesn't mean that a customer won't do it.
Chuckle.
But please, don't!
What Paul said!
Chuck
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