RE: [Q] what difference between PK and unique index + not NULL??

  • From: "Powell, Mark D" <mark.powell@xxxxxxx>
  • To: oracle-l@xxxxxxxxxxxxx
  • Date: Tue, 18 Jan 2005 14:24:13 -0500

The definition of a PK constraint is that it is a UK constraint plus the
"not null" constraint.  Indexing is a technical implementation issue and is
not really part of the PK definition.  After all Oracle can from verion 8 up
use non-unique indexes to implement PK constraints.


-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx
[mailto:oracle-l-bounce@xxxxxxxxxxxxx]On Behalf Of dba1 mcc
Sent: Tuesday, January 18, 2005 1:59 PM
To: oracle-l@xxxxxxxxxxxxx
Subject: [Q] what difference between PK and unique index + not NULL??


I have some argued with contractor about Primary key
and Unique index +  Not NULL.  Contractor said Primary
Key =  (field specify NOT NLL and create unique index
..).  I rember some documents say Primary Key and
(unique index, not null) still some different.

Does anyone have opinion?

Thanks.   


                
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