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When we can declare a column as Unique and Not Null both at
the same time. What is the use pf Primary Key then?

Question Posted / swapna

Answers were Sorted based on User's Feedback



When we can declare a column as Unique and Not Null both at the same time. What is the use pf Pri..

Answer / thanga prabu.n

Unique Key creates Non-Cluster index in default,
But in Primary Key creates Cluster index in default

Is This Answer Correct ?    16 Yes 1 No

When we can declare a column as Unique and Not Null both at the same time. What is the use pf Pri..

Answer / swapna

The concept of adding an unique key and not null constraint
to a column as well as adding as unique index to it , you
will assume to get the benefits of adding an primary key
to that column.

But use it for the purpose of referential integrity will
not allow to do so.

That's what PK is so useful. You will use it for
normalization purpose.

Is This Answer Correct ?    12 Yes 6 No

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