| Foreign Keys vs. custom scripts [message #132855] |
Tue, 16 August 2005 07:54  |
andogs
Messages: 1
Registered: August 2005
Location: Narvik, Norway
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Junior Member |
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My database/application vendor insists on using scripts/procedures in order of keeping consistance/constraints in table relations, while I mean that foreign keys/relations were made to to this job, and is not affecting performance.
Can anybody give their opinions regarding this? Where can I find documentation?
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| Re: Foreign Keys vs. custom scripts [message #133021 is a reply to message #132861] |
Wed, 17 August 2005 05:19  |
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Maaher
Messages: 7065
Registered: December 2001
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Senior Member |
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I was reading an AskTom thread about it, here's an excerpt:
| Tom Kyte on his thread "FK where ever possible" |
It is stupid to enforce it via the application AND I'll betcha $5 they aren't
even doing it right (eg: when they delete from the parent, do the LOCK the
entire child table first? Else what is to prevent another session from
inserting a child record that points to this parent that is going to be deleted.
The probably coded something like:
select count(*) from child where fk = :pk;
if count was zero then delete from parent where pk = fk;
During the count, someone is inserting -- you won't see that, they delete -
ORPHAN child)
It is excessively, extremely, very difficult to do RI all by yourself.
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But I think Mahesh already pointed this out: "database are made for this". Relational databases that is, of course.
MHE
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