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Is primary key = unique key,not null?
If yes,please explain
IF No,please explain
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Answer Posted / anamika niit
Primary key and unique are Entity integrity constraints
Primary key allows each row in a table to be uniquely
identified and ensures that no duplicate rows exist and no
null values are entered.
Unique key constraint is used to prevent the duplication of
key values within the rows of a table and allow null
values. (In oracle, one null is not equal to another null).
| Is This Answer Correct ? | 16 Yes | 2 No |
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