Computer Science
Differentiate between primary key and foreign key.
Relational Database
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Answer
| Primary Key | Foreign Key |
|---|---|
| Primary Key is a column or group of columns in a table that uniquely identify every row in that table. | A foreign key is an attribute whose value is derived from the primary key of another table. A foreign key is used to represent the relationship between two tables. |
| Primary key cannot have Null values. | Foreign key can have Null values. |
| There can be only one primary key in a table. | Multiple foreign keys can exist in a table. |
| It is used to enforce entity integrity and ensure data uniqueness. | It is used to enforce referential integrity and maintain data consistency across related tables. |
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