Is primary key = unique key,not null?
If yes,please explain
IF No,please explain
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Answer Posted / chandrika
if we define unique key column to not null
then first attempt it not allow to insert null value in
column but after inserting once we can edit its value to
null even if it is not null ( means its allow null)
if we assign primary key then its not allow (in every
situation it not allow null and duplication)
that is main difference between unique key and primery key
| Is This Answer Correct ? | 0 Yes | 7 No |
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