Description: The ‘On Delete’ action in relational databases refers to a referential integrity mechanism that defines the behavior of rows in a database when a row that is being referenced by others is deleted. This concept is fundamental for maintaining data consistency in a relational database. When a relationship between tables is established, it is common for one table to contain foreign keys pointing to primary keys in another table. The ‘On Delete’ action allows specifying what should happen to these referenced rows when the original row is deleted. Typical options include ‘CASCADE’, which automatically deletes the referenced rows, ‘SET NULL’, which sets the foreign keys to NULL, and ‘RESTRICT’, which prevents deletion if references exist. This functionality is crucial to avoid creating orphaned data and to ensure that relationships between data remain logically and structurally sound. In summary, ‘On Delete’ is a powerful tool in database management that helps developers define the behavior of relationships between tables, ensuring data integrity over time.
