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08.14.2006 at 07:36AM PDT, ID: 21953519
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7.6

Composite primary key question

Asked by dentyne in Oracle Database

Tags: , ,

I have a table that has a composite primary key with three fields.  This table has child tables so this key would be part of the primary keys on those.  Personally, I like it like this and feel it is correct modeling.   A suggestion has been made though to create a numeric ID to be the key of this table and then enforce the uniqueness of the record by placing unique constraints on the three fields that made up the composite key.  The reasoning was that (a) queries would be easier to write and (b) performance would be better.  I don't have that kind of in-depth knowledge to say yes or no, but was wondering if you could help.  

As a recap, here are the scenarios:

SCENARIO 1:  Keep the composite key:

PK1, FK1:  FK_RECORD_ID
PK1, FK1:  FK_TRANS_TYPE
PK1, FK1:  FK_YEAR


SCENARIO 2:  Create some unique numeric number and enforce the uniqueness of the record by placing some kind of constraint that those three fields need to be unique.  Is it even possible to do a three field constraint?

PK1:  UNIQUE_ID
=============
FK_RECORD_ID       \
FK_TRANS_TYPE      |--- These three fields (together) must not repeat.
FK_YEAR                /
other fields
.
.
.


Can you provide:
1.  The best solution
2.  The "pros and cons" of scenario 1 vs. scenario 2
3.  If Scenario 2 is chosen, please explain how to add a constraint that the three fields -together- have to be unique.

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[+][-]08.14.2006 at 08:07AM PDT, ID: 17310719

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About this solution

Zone: Oracle Database
Tags: composite, key, primary
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Solution Provided By: rkogelhe
Participating Experts: 2
Solution Grade: A
 
 
[+][-]08.14.2006 at 12:37PM PDT, ID: 17312882

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[+][-]08.14.2006 at 05:45PM PDT, ID: 17314831

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[+][-]08.15.2006 at 02:00AM PDT, ID: 17316390

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[+][-]08.17.2006 at 03:05AM PDT, ID: 17332783

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[+][-]08.17.2006 at 07:31AM PDT, ID: 17334462

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[+][-]08.18.2006 at 03:49AM PDT, ID: 17341203

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[+][-]08.22.2006 at 08:39AM PDT, ID: 17364749

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