Re: foreign key constraint versus referential integrity constraint
From: paul c <toledobythesea_at_oohay.ac>
Date: Sun, 25 Oct 2009 03:56:09 GMT
Message-ID: <t%PEm.49234$Db2.35658_at_edtnps83>
>
> What reason would one have to define an equality comparison to compare
> employee ids with department ids or with names? Or charge with current
> or potential? Or age with price?
Date: Sun, 25 Oct 2009 03:56:09 GMT
Message-ID: <t%PEm.49234$Db2.35658_at_edtnps83>
Bob Badour wrote:
> paul c wrote:
>
>> Bob Badour wrote: >> ... >> >>> You asked about semantic joinability. Semantically, the join works if >>> like-named attributes have an equality comparison defined and not if >>> they don't. >>> ... >> >> In RT, how could they not define equality?
>
> What reason would one have to define an equality comparison to compare
> employee ids with department ids or with names? Or charge with current
> or potential? Or age with price?
None in theory, I thought you were talking about attributes in the same domain. Received on Sun Oct 25 2009 - 04:56:09 CET