Re: Tables Larger When using DBMS_REDEFINITION

From: Mladen Gogala <>
Date: Mon, 23 Feb 2015 23:57:33 -0500
Message-ID: <>

On 02/23/2015 10:55 PM, Tim Gorman wrote:
> Joining this thread late, but vocabulary is important. Don't confuse
> "primary keys" with "primary key constraints". The former is a
> combination of column values to uniquely identify a row, the latter is
> a mechanism used to enforce the former.
> Just because a table doesn't employ primary key constraints doesn't
> mean that it doesn't have a primary key, and that it is not enforced.

Hi Tim,
What's the point in having a not-null unique index, which can act as a primary key, and not defining constraint? If there is a set of columns that can be used to enforce primary key, then defining the primary constraint only formalizes the relationship, sort of marriage certificate, which certifies the unity of the table and its PK, until DROP TABLE takes them apart.

Mladen Gogala
Oracle DBA

Received on Tue Feb 24 2015 - 05:57:33 CET

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