Is primary key = unique key,not null?
If yes,please explain
IF No,please explain
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Answer Posted / kirti
Yes.When a column is assigned primary key it means it
contains unique value(i.e. no duplicate value is allowed) &
it can't accept null values.
Whereas unique key means no duplicare value is allowed, but
null value is allowed. And not null means no null value is
accepted but duplicate value can be passed.
So when we assign primary key to a column, the column
becomes both unique & not null.
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