What is the main different between Null and NOT Null.
Difference between Primary and Unique Key.
How to Check the database from which application is it
possibe.
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Answer Posted / nivedita
IF NULL is specified,the feild is allow to be left empty
without any value.
IF NOT NULL is specified,the field must be given a value. In
the absence of either a NULL or NOT NULL, NULL is assumed.
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Unique key can't be NULL.Primary key can be NULL.
Unique key always contain unique value,duplicate are not
allowed(genrally the system genrated key).Primary key maybe
repeated.
| Is This Answer Correct ? | 6 Yes | 35 No |
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