Difference between primary key and unique key ?
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Answer Posted / chintan desai
Primary key don't have any null value, each table have only
one primary key. Not support duplicate value.
Unique key is uniquely identify, more then one unique key
allow in table.
Here the main different is what primary key do not have any
null value where unique key have only one null value.
Ex: here t1 is the name of table which have two field id and
name. here id is identify as a unique key then unique key's
null value look like under bellow:
1 chintan
NULL komal
2 ck
NULL NULL
| Is This Answer Correct ? | 2 Yes | 3 No |
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