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| − | '''Primary Key''' | + | '''Primary Key''' | '''Surrogate Key''' |
| − | + | Primary Key is a constraint that ensures that the column or set of columns so designated should not have duplicate or null values . | Surrogate Key is a column or set of colums that can be declared as primary key instead of a natural or real key. | |
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Latest revision as of 14:10, 1 April 2015
The primary key and the surrogate key both are unique identifiers for the entity in the modelled world or object in the database. However , they have a difference which is based on the type of the database being used.
| Primary Key | Surrogate Key |
|---|---|
| Primary Key is a constraint that ensures that the column or set of columns so designated should not have duplicate or null values . | Surrogate Key is a column or set of colums that can be declared as primary key instead of a natural or real key. |