Re: O'Reilly interview with Date
From: Kenneth Downs <knode.wants.this_at_see.sigblock>
Date: Thu, 11 Aug 2005 15:24:21 -0400
Message-Id: <s5lss2-lk1.ln1_at_pluto.downsfam.net>
>>
>> personally i distinguish them with a prefix code, which is put onto the
>> end of the column(s) names.
>> which is equivalent to the following DDL:
>>
>> create table examples (
>> SOMECOLUMN int PRIMARY KEY
>> )
>>
>> create table examples_xref (
>> SOMECOLUMN int REFERENCES examples(SOMECOLUMN),
>> SOMECOLUMN_TO int REFERENCES examples(SOMECOLUMN)
>> )
Date: Thu, 11 Aug 2005 15:24:21 -0400
Message-Id: <s5lss2-lk1.ln1_at_pluto.downsfam.net>
Paul wrote:
> Kenneth Downs wrote: >>>>In my own system I never manually code a join, I just specify the two >>>>tables and it builds it out of the foreign key definitions. >>> >>>What if there is more than one foreign key constraint involving the two >>>tables?
>>
>> personally i distinguish them with a prefix code, which is put onto the
>> end of the column(s) names.
> > <snip> >
>> which is equivalent to the following DDL:
>>
>> create table examples (
>> SOMECOLUMN int PRIMARY KEY
>> )
>>
>> create table examples_xref (
>> SOMECOLUMN int REFERENCES examples(SOMECOLUMN),
>> SOMECOLUMN_TO int REFERENCES examples(SOMECOLUMN)
>> )
> > OK maybe I'm being dense here, but when you now specify your two tables, > "examples" and "examples_xref", how does the system know which of the > foreign key constraints to use to generate the join? >
-- Kenneth Downs Secure Data Software, Inc. (Ken)nneth_at_(Sec)ure(Dat)a(.com)Received on Thu Aug 11 2005 - 21:24:21 CEST