Re: What is unique_id in Oracle and what's the use of it

From: venki <>
Date: Wed, 30 Jan 2008 03:01:04 -0800 (PST)
Message-ID: <>

On Jan 30, 8:47 am, newa <> wrote:
> Hi,
> I am new to Oracle and today someone asked me about the "fference
> between unique_id and primary key. Which to use and why?" I know about
> the primary key but not unique_id. Can someone kindly give me an
> overview of it?
> Thanks in advance.

Primary key is the combination of NOTNULL constraint and unique key constraint.
so it ll never allow duplicate and null value.But unique key allows number of null value but it never allow duplicate value. Do not compare this to MS sqlserver, bcoz it some what different from oracle to sql. Bcoz unique key will alow only one null value.

venki Received on Wed Jan 30 2008 - 05:01:04 CST

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