Re: Recursive relationship

From: Chris Royce <Chris_at_Royce.net>
Date: Tue, 20 Jun 2000 21:36:50 -0400
Message-Id: <10534.109930@fatcity.com>

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Can you test that ?? And forward the results ?? iT MAY WELL BE ok ?? Surprised that it passed!! One learns every day!!

Louis Avrami wrote:

> Hi all,
>
> I was looking at one of the development databases here at my
> shop and came across the following constraint on a table:
>
> REM Generating create SQL for: CIRQIT.ITEM foreign constraint:
> SYS_C009488
> ALTER TABLE ITEM ADD CONSTRAINT SYS_C009488 FOREIGN KEY (
> ITEM_NBR ,
> VERSION_NBR )
> REFERENCES CIRQIT.ITEM (
> ITEM_NBR ,
> VERSION_NBR ) ;
>
> I was a little surprised that Oracle (8.1.6.0.0) even allowed
> for a self-referencing foreign key constraint to be created.
>
> Can anyone out there give a "formal" explanation or references
> as to why such a recursive relationship is not good? I've used
> the terms "recursive relationship" and "keys referring back to
> themselves", etc. etc.
>
> Thanks
>
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> --
> Author: Louis Avrami
> INET: avramil_at_concentric.net
>
> Fat City Network Services -- (858) 538-5051 FAX: (858) 538-5051
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Can you test that ?? And forward the results ?? iT MAY WELL BE ok ?? Surprised that it passed!!  One learns every day!!

<p>Louis Avrami wrote:
<blockquote TYPE=CITE>Hi all,
<p>I was looking at one of the development databases here at my
<br>shop and came across the following constraint on a table:
<p>REM Generating create SQL for: CIRQIT.ITEM&nbsp;&nbsp;&nbsp;&nbsp; foreign

constraint:

<br>&nbsp; SYS_C009488
<br>ALTER TABLE ITEM ADD CONSTRAINT SYS_C009488 FOREIGN KEY (
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; ITEM_NBR&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;

,
        VERSION_NBR                        )
  REFERENCES CIRQIT.ITEM (
        ITEM_NBR                           ,
        VERSION_NBR                        ) ;

<p>I was a little surprised that Oracle (8.1.6.0.0) even allowed
<br>for a self-referencing foreign key constraint to be created.
<p>Can anyone out there give a "formal" explanation or references
<br>as to why such a recursive relationship is not good?&nbsp; I've used
<br>the terms "recursive relationship" and "keys referring back to
<br>themselves", etc. etc.
<p>Thanks
<p>----------------
<br>Sent from a WebBox - <a href="http://www.webbox.com">http://www.webbox.com</a>
<br>FREE Web based Email, Files, Bookmarks, Calendar, People and
<br>Great Ways to Share them with Others!
<p>--
<br>Author: Louis Avrami
<br>&nbsp; INET: avramil_at_concentric.net
<p>Fat City Network Services&nbsp;&nbsp;&nbsp; -- (858) 538-5051&nbsp;

FAX: (858) 538-5051
 San Diego, California        -- Public Internet access / Mailing Lists

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<br>to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in

the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from).  You may
 also send the HELP command for other information (like subscribing).</blockquote> Received on Tue Jun 20 2000 - 20:36:50 CDT