Re: URGENT: Primary key vs Unique Index

In article <33133DFD.6162_at_mediadata.com.sg>,

   Mars <mars_at_mediadata.com.sg> wrote:
>Pardon my ignorance but why can't a primary key be NULL ? Is it a rule
>or is it specific to just Oracle ?

A primary key generally serves to uniquely identify each record in a table. Thus, a primary key being NULL would mean something like "I don't know what this record is about", something we don't like to see in a database.

Stefan.

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