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difference???? [message #19192] Mon, 04 March 2002 18:55 Go to next message
jeya
Messages: 18
Registered: January 2001
Junior Member
what is the difference between
PRIMARY KEY and UNIQUE NOT NULL
both serves the same purpose.
if so...y we go for primary key instead of unique not null??
Re: difference???? [message #19193 is a reply to message #19192] Mon, 04 March 2002 19:52 Go to previous message
Somu
Messages: 24
Registered: February 2000
Junior Member
Hi,

The major difference between Primary Key and the Unique Index is

The primary key can be used for the Foreign key reference, but the Unique index does not solve this.

We can have multiple unique index in a table, but we can have only one primary key in a table.
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