Re: Concatenated Primary Key

From: <syakobson_at_my-dejanews.com>
Date: Tue, 28 Jul 1998 02:53:59 GMT
Message-ID: <6pjeg7$c9j$1@nnrp1.dejanews.com>

In article <35bc8854.0_at_news.rlcn.rl.af.mil>, reichmanm_at_removethis.rl.af.mil. (Mark S. Reichman) wrote:
> In the book "Building Intelligent Databases with Oracle PL/SQL
> Triggers and Procedures" the author on page 59 says the
> individual columns of a concatenated primary key can be null as long
> as at least one of the columns is not null.

I did not read the book, but it definitely is a typo. ALL primary key columns must have NOT NULL values. If some of key columna can be null you should use UNIQUE constraint rather than PRIMARY KEY constraint.

Solomon Yakobson

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