RE: Primary Keys optional?

  • From: "Guerra, Abraham J" <AGUERRA@xxxxxxxxx>
  • To: <andert@xxxxxxxxx>, <oracle-l@xxxxxxxxxxxxx>
  • Date: Thu, 17 Aug 2006 11:53:16 -0500

Is there referential integrity?  You need PK for RI.

Abraham Guerra

-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx] On Behalf Of Stephen Andert
Sent: Thursday, August 17, 2006 11:47 AM
To: oracle-l@xxxxxxxxxxxxx
Subject: Primary Keys optional?

OK, just starting a new job with more design than I have done in a
while.  Looking into things, I have been noticing that many tables
have no PK.  Some have a unique index, but not all.

When I pointed this out to folks (developers) they shrugged and said
"if you need a PK, then create one".

So my questions are:

1. Is it considered acceptable to have a unique index instead of a pk?

2. What are the circumstances when a table might be allowed to exist
without any sort of primary key or unique index?  (i.e. temp table,
static small table, etc)

Thanks In Advance

Stephen Andert

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