Key Constraints – PRIMARY KEY, FOREIGN KEY :
PRIMARY KEY:
Primary key
uniquely identifies each record in a table. It must have unique values
and cannot contain nulls. In the below example the ROLL_NO field is
marked as primary key, that means the ROLL_NO field cannot ...
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3,999
5,499
27% off
999
1,499
33% off
5.0
4.5
999
5.0
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