Description: The ‘On Update’ action in SQLite refers to a referential action that specifies what happens to a row when the referenced row is updated. This mechanism is part of the referential integrity constraints that help maintain data consistency in a relational database. When a relationship between two tables is established, it is crucial to define how updates in the referenced table should be handled to avoid inconsistencies. The actions that can be specified include ‘CASCADE’, which propagates the update to related rows; ‘SET NULL’, which sets the values of related columns to NULL; and ‘SET DEFAULT’, which assigns a default value to related columns. These options allow developers to effectively manage relationships between data, ensuring that any changes in one table do not cause errors or loss of information in another. Implementing these actions is essential for maintaining data integrity and facilitating the management of complex databases where multiple tables may be interconnected. In summary, ‘On Update’ is a vital tool in database design that helps maintain data consistency and integrity over time.
