Re[2]: Limits on referential integrity

From: <dgoulet_at_vicr.com>
Date: Tue, 22 Jan 2002 08:28:46 -0800
Message-ID: <F001.003F7046.20020122062026@fatcity.com>

Agree on both counts. The simple solution, which I believe is stated in the Oracle Concepts manuals is that all foreign keyed columns should also be indexed. A step sadly not taken in this particular case. Love it when you can make a simple suggestion & fix the problem!!

Dick Goulet

____________________Reply Separator____________________
Author: orantdba <orantdba_at_netscape.net>
Date:       1/22/2002 8:07 AM

Hi Dennis,

Agreed this was not the developers fault, it was the DBA's! I don't blame this on RI being handled by constraints, but on a DBA that doesn't understand
the consequences, the resulting table level lock could have also been a problem :-).
BTW, if RI had been handled via the application they would have had the same
problem.

John

dgoulet_at_vicr.com wrote:

>John,
>
> I have only seen one situation where referential integrity has caused a
>problem that the developer could not prevent. That case involved a foreign key
>with the 'on delete cascade' option turned on and the key column in the child
>table was NOT indexed. OH, BTW the child table was well lets just say VERY
>large (2 billion rows).
>
>Dick Goulet
>
>____________________Reply Separator____________________
>Subject: Re: Limits on referential integrity
>Author: orantdba <orantdba_at_netscape.net>
>Date: 1/22/2002 5:40 AM
>
>
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>Content-Transfer-Encoding: 7bit
>
>Hi Dennis,
>
>Just my opinion but I tried to follow these rules as a DBA.
>
>1. If the business rule can be implemented with pk, fk, unique or check
>constraints I do it as such
>2. If the business rule can be implemented as a trigger I code it as a
>trigger
>3. If none of the above, I implement as a stored procedure and try to
>insure that every developer uses this procedure.
>
>Occasionally I have heard the "performance discussion" in regards to
>constraints. In 5 years of consulting I have never had constraints be
>THE problem. But if I was a developer that had written some of the
>awful SQL I have seen, I might have tried [:-)] . Constraints do put a
>premium on error checking by the application on inserts/updates.
>
>Hope this helps,
>John
>
>
>
>DWILLIAMS_at_LIFETOUCH.COM wrote:
>
>>Jared - I wasn't clear, but then again it is Monday. I have a team of
>>inexperienced developers starting a big, new Java application. They have a
>>good, experienced data model consultant helping them create the data model.
>>They are eager to include referential integrity. So eager it has me a little
>>worried. My question: "Is there too much of a good thing?". In Oracle 7,
>>sometimes sites would remove RI to ensure good performance (we are starting
>>this project on Oracle9i). Has anyone encountered problems with too many
>>constraints? Any guidelines you use with developers? Thanks.
>>Dennis Williams
>>DBA
>>Lifetouch, Inc.
>>dwilliams_at_lifetouch.com
>>
>>
>>-----Original Message-----
>>Sent: Monday, January 21, 2002 4:16 PM
>>To: Multiple recipients of list ORACLE-L
>>
>>
>>I would be you lunch that what they are implementing in their
>>code is not actually RI. They may be implementing code to
>>ensure things get inserted in the right order, and that child rows
>>have a parent.
>>
>>This is a very weak form of RI. Oracle is very good at implementing
>>RI, and it is not dependent on an application. RI in the database
>>is the route to choose unless there is some good reason not to.
>>
>>RI in the database will prevent orphaned data created through
>>updates, deletes or even ( gasp! ) bugs in the app.
>>
>>Programmers tend to dislike RI in the database because it
>>forces them to maintain data integrity in a transaction. This is
>>not a bad thing, it just forces them to have a good understanding
>>of their transactions.
>>
>>Point out to them that it is less code to write as well. :)
>>
>>Jared
>>
>>
>>
>>
>>
>>
>>
>>DENNIS WILLIAMS <DWILLIAMS_at_LIFETOUCH.COM>
>>Sent by: root_at_fatcity.com
>>01/21/02 01:35 PM
>>Please respond to ORACLE-L
>>
>>
>> To: Multiple recipients of list ORACLE-L <ORACLE-L_at_fatcity.com>
>> cc:
>> Subject: Limits on referential integrity
>>
>>
>>How much referential integrity should be implemented in Oracle? We are
>>starting a large new Java project. Our current applications keep their
>>referential integrity inside their own dictionary, so I haven't had to
>>deal
>>much with referential integrity recently. Can there be too much of a good
>>thing? What guidelines do you tend to use? At this point the developers
>>are
>>designing the data model so they are busily linking all the little boxes.
>>My
>>attitude at this point is "implement what you've got and if there are
>>performance problems we'll deal with them when they arise". Can anyone
>>give
>>me a better motto?
>>Thanks.
>>Dennis Williams
>>DBA
>>Lifetouch, Inc.
>>dwilliams_at_lifetouch.com
>>
>
>
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><pre wrap="">Hi Dennis,
>
>Just my opinion but I tried to follow these rules as a DBA.
>
>1. If the business rule can be implemented with pk, fk, unique or check
>constraints I do it as such
>2. If the business rule can be implemented as a trigger I code it as a
>trigger
>3. If none of the above, I implement as a stored procedure and try to
>insure that every developer uses this procedure.
>
>Occasionally I have heard the "performance discussion" in regards to
>constraints. In 5 years of consulting I have never had constraints be
>THE problem. But if I was a developer that had written some of the
>awful SQL I have seen, I might have tried <img
>src="chrome://editor/content/images/smile_n.gif" alt=":-)"
class="moz-txt-smily"
>height="19" width="19" align="Center">. Constraints do put a
>premium on error checking by the application on inserts/updates.
>
>Hope this helps,
>John</pre>
> 
> 
><a class="moz-txt-link-abbreviated"
>href="mailto:DWILLIAMS_at_LIFETOUCH.COM">DWILLIAMS_at_LIFETOUCH.COM</a> wrote: 
><blockquote type="cite" cite="mid:md5%3A64756D6D79206D657373616765206964">
> <pre wrap="">Jared - I wasn't clear, but then again it is Monday. I have a
>team of inexperienced developers starting a big, new Java application. They
>have a good, experienced data model consultant helping them create the data
>model. They are eager to include referential integrity. So eager it has me a
>little worried. My question: "Is there too much of a good thing?". In Oracle
>7, sometimes sites would remove RI to ensure good performance (we are
>starting this project on Oracle9i). Has anyone encountered problems with too
>many constraints? Any guidelines you use with developers? Thanks. Dennis
>Williams DBA Lifetouch, Inc. <a class="moz-txt-link-abbreviated"
>href="mailto:dwilliams_at_lifetouch.com">dwilliams_at_lifetouch.com</a> --
-
>--Original Message----- Sent: Monday, January 21, 2002 4:16 PM To:
>Multiple recipients of list ORACLE-L I would be you lunch that what
>they are implementing in their code is not actually R
>I. They may be implementing code to ensure things get inserted in the
right
>order, and that child rows have a parent. This is a very weak form of
>RI. Oracle is very good at implementing RI, and it is not dependent on an
>application. RI in the database is the route to choose unless there is some
>good reason not to. RI in the database will prevent orphaned data
created
>through updates, deletes or even ( gasp! ) bugs in the
>app. Programmers tend to dislike RI in the database because it forces
>them to maintain data integrity in a transaction. This is not a bad thing,
>it just forces them to have a good understanding of their
>transactions. Point out to them that it is less code to write as well.
>:) Jared DENNIS WILLIAMS <a
>class="moz-txt-link-rfc2396E"
>href="mailto:DWILLIAMS_at_LIFETOUCH.COM"><DWILLIAMS_at_LIFETOUCH.COM></a> Sen
>t by: <a class="moz-txt-link-abbreviated" href="mailto:r!
>o !
>!
>ot_at_fatcity.com">root_at_fatcity.com</a> 01/21/02 01:35 PM Please respond to
>ORACLE-L To: Multiple recipients of list ORACLE-L <a
>class="moz-txt-link-rfc2396E"
>href="mailto:ORACLE-L_at_fatcity.com"><ORACLE-L_at_fatcity.com></a> 
>cc: Subject: Limits on referential integrity How
>much referential integrity should be implemented in Oracle? We are starting
a
>large new Java project. Our current applications keep their referential
>integrity inside their own dictionary, so I haven't had to deal much
with
>referential integrity recently. Can there be too much of a good thing? What
>guidelines do you tend to use? At this point the developers
 are designing
>the data model so they are busily linking all the little boxes.
> My attitude at this point is "implement what you've got and if there
>are performance problems we'll deal with them when they arise". Can anyone
> give me a better motto?
> Thanks. Dennis Williams DBA Lifetouch, Inc. <a
>class="moz-txt-link-abbreviated"
>href="mailto:dwilliams_at_lifetouch.com">dwilliams_at_lifetouch.com</a> </pre>
> </blockquote>
> 
> </body>
> </html>
>
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>

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Hi Dennis, 
 
Agreed this was not the developers fault,  it was the DBA's!  I don't blame
 
this on RI being handled by constraints, but on a DBA that doesn't understand 
the consequences, the resulting table level lock could have also been a problem :-).   
BTW, if RI had been handled via the application they would have had the same 
problem. 
 
John 
 
<a class="moz-txt-link-abbreviated"
href="mailto:dgoulet_at_vicr.com">dgoulet_at_vicr.com</a> wrote: <blockquote type="cite" cite="mid:md5%3A64756D6D79206D657373616765206964"> <pre wrap="">John, I have only seen one situation where referential integrity has caused a problem that the developer could not prevent. That

case involved a foreign key<br>with the 'on delete cascade' option turned on and
the key column in the child<br>table was NOT indexed.  OH, BTW the child table
was well lets just say VERY<br>large (2 billion rows).<br><br>Dick
Goulet<br><br>____________________Reply
Separator____________________<br>Subject:    Re: Limits on referential

integrity Author: orantdba <a class="moz-txt-link-rfc2396E" href="mailto:orantdba_at_netscape.net"><orantdba_at_netscape.net></a> Date:

1/22/2002 5:40
AM --------------020102080806060304030001 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Hi Dennis, Just my opinion but I tried to follow these rules as a DBA. 1. If the business rule can be implemented with pk, fk, unique or check constraint
s I do it as such 2. If the business rule can be implemented as a trigger I code it as a trigger 3. If none of the above, I implement as a stored procedure and try to insure that every developer uses this procedure. Occasionally I have heard the "performance discussion" in regards to constraints. In 5 years of consulting I have never had constraints be THE problem. But if I was a developer that had written some of the awful SQL I have seen, I might have tried [:-)] . Constraints do put a premium on error checking by the application on inserts/updates. Hope this helps, John <a class="moz-txt-link-abbreviated"
href="mailto:DWILLIAMS_at_LIFETOUCH.COM">DWILLIAMS_at_LIFETOUCH.COM</a> wrote: </pre>
 <blockquote type="cite">
 <pre wrap="">Jared - I wasn't clear, but then again it is Monday. I have a team of inexperienced developers starting a big, new Java application. They

have a<br>good, experienced data model consultant helping them create the data
model.<br>They are eager to include referential integrity. So eager it has me a
little<br>worried. My question: "Is there too much of a good thing?". In Oracle

7, sometimes sites would remove RI to ensure good performance (we are starting this project on Oracle9i). Has anyone encountered problems with too many constraints? Any guidelines you use with developers? Thanks. Dennis Williams DBA Lifetouch, Inc. <a class="moz-txt-link-abbreviated" href="mailto:dwilliams_at_lifetouch.com">dwilliams_at_lifetouch.com</a> --- --Original Message----- Sent: Monday, January 21, 2002 4:16 PM To: Multiple recipients of list ORACLE-L I would be you lunch that what they are implementing in their code is not actually RI. They may be implementing code to ensure things get inserted in the right order, and that child rows have a parent. This is a very weak form of RI. Oracle is very good at implementing RI, and it is not dependent on an application. RI in the database is the route to choose unless there is some good reason not to. RI in the database will prevent orphaned data created through updates, deletes or even ( gasp! ) bugs in the app. Programmers tend to dislike RI in the database because it forces them to maintain data integrity in a transaction. This is not a bad thing, it just forces them to have a good understanding of their transactions. Point out to them that it is less code to write as well. :) Jared DENNIS WILLIAMS <a class="moz-txt-link-rfc2396E"
href="mailto:DWILLIAMS_at_LIFETOUCH.COM"><DWILLIAMS_at_LIFETOUCH.COM></a> Sen t by: <a class="moz-txt-link-abbreviated" href="mailto! : root_at_fatcity.com">root_at_fatcity.com</a> 01/21/02 01:35 PM Please respond to ORACLE-L To: Multiple recipients of list ORACLE-L <a class="moz-txt-link-rfc2396E"

href="mailto:ORACLE-L_at_fatcity.com">&lt;ORACLE-L_at_fatcity.com&gt;</a><br>      
cc: <br>       Subject:        Limits on referential integrity<br><br><br>How

much referential integrity should be implemented in Oracle? We are starting a large new Java project. Our current applications keep their referential integrity inside their own dictionary, so I haven't had to deal much with referential integrity recently. Can there be too much of a good thing? What guidelines do you tend to use? At this point the developers are designing the data model so they are busily linking all the little boxes. My attitude at this point is "implement what you've got and if there are performance problems we'll deal with them when they arise". Can anyone give me a better motto?!
Thanks. Dennis Williams DBA Lifetouch, Inc. <a class="moz-txt-link-abbreviated"
href="mailto:dwilliams_at_lifetouch.com">dwilliams_at_lifetouch.com</a> </pre>

</blockquote>
<pre
wrap=""> --------------020102080806060304030001 Content-Type: multipart/related; 
boundary="------------InterScan_NT_MIME_Boundary" --------------I nterScan_NT_MIME_Boundary Content-Type: multipart/alternative; boundary="------------020102080806060304030001" boundary="------------070606010707000609020708" --------------07060601070 7000609020708 Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <html> <head> </head> <body> &lt ;pre wrap="">Hi Dennis, Just my opinion but I tried to follow these rules as a DBA. 1. If the business rule can be implemented with pk, fk, unique or check constraints I do it as such 2. If the business rule can be implemented as a trigger I code it as a trigger 3. If none of the above, I implement as a stored procedure and try to insure that every developer uses this procedure.<br!
> Occasionally I have heard the "performance discussion" in regards to

<br>constraints.  In 5 years of consulting I have never had constraints be
<br>THE problem.  But if I was a developer that had written some of the
<br>awful SQL I have seen, I might have tried &lt;img<br>src=<a

class="moz-txt-link-rfc2396E"
href="chrome://editor/content/images/smile_n.gif">"chrome://editor/content/image s/smile_n.gif"</a> alt=":-)" class="moz-txt-smily" height="19" width="19" align="Center">. Constraints do put a premium on error checking by the application on inserts/updates. Hope this helps, John</pre> <a class="moz-txt-link-abbreviated" href=<a class="moz-txt-link-rfc2396E" href="mailto:DWILLIAMS_at_LIFETOUCH.COM">"mailto:DWILLIAMS_at_LIFETOUCH.COM"</a>><a class="moz-txt-link-abbreviated"
href="mailto:DWILLIAMS_at_LIFETOUCH.COM">DWILLIAMS_at_LIFETOUCH.COM</a></a> wrote: <blockquote type="cite" cite="mid:md5! %3
A64756D6D79206D657373616765206964"> <pre wrap="">Jared - I wasn't clear, but then again it is Monday. I have a team of inexperienced developers starting a big, new Java application. They have a good, experienced data model consultant helping them create the data model. They are eager to include referential integrity. So eager it has me a little worried. My question: "Is there too much of a good thing?". In Oracle 7, sometimes sites would remove RI to ensure good performance (we are starting this project on Oracle9i). Has anyone encountered problems with too many constraints? Any guidelines you use with developers?
Thanks. Dennis Williams DBA Lifetouch, Inc. <a class="moz-txt-link-abbreviated" href=<a class="moz-txt-link-rfc2396E"
href="mailto:dwilliams_at_lifetouch.com">"mailto:dwilliams_at_lifetouch.com"</a>><a class="moz-txt-link-abbre!
v iated"
href="mailto:dwilliams_at_lifetouch.com">dwilliams_at_lifetouch.com</a></a> --- --Original Message----- Sent: Monday, January 21, 2002 4:16 PM To: Multiple recipients of list ORACLE-L I would be you lunch that what they are implementing in their code is not actually R I. They may be implementing code to ensure things get inserted in the right order, and that child rows have a parent. This is a very weak form of RI. Oracle is very good at implementing RI, and it is not dependent on an application. RI in the database is the route to choose unless there is some good reason not to. RI in the database will prevent orphaned data created through updates, deletes or even ( gasp! ) bugs in the app. Programmers tend to dislike RI in the database because it&l! t;b
r>forces them to maintain data integrity in a transaction. This is not a bad thing, it just forces them to have a good understanding of their transactions. Point out to them that it is less code to write as
well. :) Jared DENNIS WILLIAMS <a class="moz-txt-link-rfc2396E" href=<a class="moz-txt-link-rfc2396E" href="mailto:DWILLIAMS_at_LIFETOUCH.COM">"mailto:DWILLIAMS_at_LIFETOUCH.COM"</a>><a

class="moz-txt-link-rfc2396E"
href="mailto:DWILLIAMS_at_LIFETOUCH.COM"><DWILLIAMS_at_LIFETOUCH.COM></a></a& gt; Sen t by: <a class="moz-txt-link-abbreviated" href="<a class="moz-txt-link-freetext" href="mailto:r">mailto:r</a>! o ! ! <a class="moz-txt-link-abbreviated"
href="mailto:ot_at_fatcity.com">ot_at_fatcity.com</a>"><a class="moz-txt-link-abbreviated"
href="mailto:root_at_fatcity.com">root_at_fatcity.com</a></a > 01/21/02 01:35 PM Please respond to ORACLE-L To: Multiple recipients of list ORACLE-L <a class="moz-txt-link-rfc2396E" href=<a

class="moz-txt-link-rfc2396E"
href="mailto:ORACLE-L_at_fatcity.com">"mailto:ORACLE-L_at_fatcity.com"</a>&gt;<a
class="moz-txt-link-rfc2396E"
href="mailto:ORACLE-L_at_fatcity.com">&lt;ORACLE-L_at_fatcity.com&gt;</a>&lt;/a&gt;&lt
;br&gt;       <br>cc: &lt;br&gt;        Subject:        Limits on referential

integrity How much referential integrity should be implemented in Oracle? We are starting a large new Java project. Our current applications keep their referential integrity inside their own dictionary, so I haven't had to deal much with referential integrity recently. Can there be too much of a good thing? What guidelines do you tend to use? At this point the developers are design ing the data model so they are busily linking all the little boxes. My attitude at this point is "implement what you've got and if there are performance problems we'll deal with them when they arise". Can anyone give me a better motto? Thanks. Dennis Williams DBA Lifetouch, Inc. <a class="moz-txt-link-abbreviated" href=<a class="moz-txt-link-rfc2396E"
href="mailto:dwilliams_at_lifetouch.com">"mailto:dwilliams_at_lifetouch.com"</a>><a class="moz-txt-link-abbreviated"
href="mailto:dwilliams_at_lifetouch.com">dwilliams_at_lifetouch.com</a></a> </pre> </blockquote> </body> 
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Received on Tue Jan 22 2002 - 10:28:46 CST