How do I use on delete cascade in mysql?

by

Here’s what you’d include in your components table.

CREATE TABLE `components` (
    `id` int(10) unsigned NOT NULL auto_increment,
    `typeId` int(10) unsigned NOT NULL,
    `moreInfo` VARCHAR(32), 
    -- etc
    PRIMARY KEY (`id`),
    KEY `type` (`typeId`)
    CONSTRAINT `myForeignKey` FOREIGN KEY (`typeId`)
      REFERENCES `types` (`id`) ON DELETE CASCADE ON UPDATE CASCADE
)

Just remember that you need to use the InnoDB storage engine: the default MyISAM storage engine doesn’t support foreign keys.

More Related Contents:

  1. MySQL Cannot Add Foreign Key Constraint
  2. Required to join 2 tables with their FKs in a 3rd table
  3. Can a foreign key reference a non-unique index?
  4. MySQL – Conditional Foreign Key Constraints
  5. How to create relationships in MySQL
  6. Is it possible to reference one column as multiple foreign keys?
  7. Foreign key constraints: When to use ON UPDATE and ON DELETE
  8. Recreating a query using INNER JOIN? [duplicate]
  9. How to perform grouped ranking in MySQL
  10. MySQL Trigger after update only if row has changed
  11. MySQL “WITH” clause
  12. MySQL “Group By” and “Order By”
  13. MySQL Query to select data from last week?
  14. Basics of Foreign Keys in MySQL?
  15. The total number of locks exceeds the lock table size
  16. update multiple rows using limit in mysql?
  17. Mysql 1050 Error “Table already exists” when in fact, it does not
  18. MySQL “IN” operator performance on (large?) number of values
  19. How to get the latest record in each group using GROUP BY? [duplicate]
  20. How do I UPDATE a row in a table or INSERT it if it doesn’t exist?
  21. SQL unique varchar case sensitivity question
  22. How do I count columns of a table
  23. Difference between two table structure
  24. Difference between SET autocommit=1 and START TRANSACTION in mysql (Have I missed something?)
  25. MySQL equivalent of Oracle’s SEQUENCE.NEXTVAL
  26. Why MySQL is giving error “Not allowed to return a result set from a function”?
  27. MySQL 5.6 – DENSE_RANK like functionality without Order By
  28. Execute INSERT if table is empty?
  29. MySQL: Computed Column
  30. How do I extract Month and Year in a MySQL date and compare them?

Leave a Comment