Referential Integrity

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Referential integrity is a fundamental concept in database management that ensures the consistency and accuracy of data relationships between tables. It is enforced through the use of foreign key constraints and ensures that relationships between tables remain valid and reliable.

Here's a breakdown of referential integrity:

  1. Definition: Referential integrity refers to the accuracy and consistency of relationships between tables in a relational database. It ensures that any foreign key value in a child table always refers to a valid primary key value in the parent table.

  2. Enforcement: Referential integrity is typically enforced through the use of foreign key constraints. A foreign key constraint specifies that the values in a particular column (the foreign key) of one table must match the values in the primary key column of another table (the referenced table).

  3. Maintaining Relationships: Referential integrity ensures that relationships between tables are maintained correctly. It prevents orphaned records (child records that refer to non-existent parent records) and ensures that all related records are consistent and up-to-date.

Actions on Referential Integrity Violations:
  • Restrict: Prevents the deletion or update of a parent record if there are dependent child records.
  • Cascade: Automatically deletes or updates dependent child records when a parent record is deleted or updated.
  • Set Null: Sets the foreign key value in child records to NULL when the referenced parent record is deleted or updated.
  • Set Default: Sets the foreign key value in child records to a default value when the referenced parent record is deleted or updated.
Benefits: Maintaining referential integrity ensures data consistency and accuracy throughout the database. It helps prevent data anomalies, such as orphaned records or inconsistent relationships, which could lead to data corruption or inaccuracies.

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