In MySQL, the ON UPDATE CASCADE option in foreign key constraints indicates that anytime an update is made to a row in the parent table, matching rows in child tables are correspondingly updated. This feature provides assurance for referential integrity and consistency of related data in a related set of tables without having to manage it manually. Knowing when and how to use ON UPDATE CASCADE is important in managing table relationships effectively and facilitating data maintenance. What is ON UPDATE CASCADE? The ON UPDATE CASCADE is an option that makes up a definition for a foreign key constraint in MySQL . If a value in the parent table column of the primary key is updated, it ensures that the matching value is changed in the foreign key column in the child table. This may be done through cascading updates , to keep relationships between related tables intact and consistent. DDL Command CREATE TABLE child_table ( child_id INT, parent_id INT, FOR