Answered by : pierre-joubert
ALTER TABLE table_name
DROP CONSTRAINT fk_name;Source : https://www.techonthenet.com/sql_server/foreign_keys/drop.php | Last Update : Thu, 11 Jun 20
Answered by : kaotik
CREATE TABLE parent ( id INT NOT NULL, PRIMARY KEY (id)
) ENGINE=INNODB;
CREATE TABLE child ( id INT, parent_id INT, INDEX par_ind (parent_id), FOREIGN KEY (parent_id) REFERENCES parent(id) ON DELETE CASCADE
) ENGINE=INNODB;Source : https://dev.mysql.com/doc/refman/5.6/en/create-table-foreign-keys.html | Last Update : Mon, 09 Mar 20
Answered by : henry-obiaraije
CREATE TABLE products( productId INT AUTO_INCREMENT PRIMARY KEY, productName varchar(100) not null, categoryId INT NOT NULL, CONSTRAINT fk_category FOREIGN KEY (categoryId) REFERENCES categories(categoryId) ON UPDATE CASCADE ON DELETE CASCADE
) ENGINE=INNODB;Source : https://www.mysqltutorial.org/mysql-foreign-key/ | Last Update : Wed, 13 Apr 22
Answered by : curious-capybara-k8379e4jpce4
SET foreign_key_checks = 0;
UPDATE languages SET id='xyz' WHERE id='abc';
UPDATE categories_languages SET language_id='xyz' WHERE language_id='abc';
SET foreign_key_checks = 1;Source : https://stackoverflow.com/questions/7541446/how-to-update-foreign-key-value-in-mysql-database | Last Update : Mon, 03 Aug 20
Answered by : clumsy-crane-elj1uxa5a79a
ALTER TABLE `tabl` ADD CONSTRAINT `constraint_name` FOREIGN KEY (`column`) REFERENCES `table2` (`id`) ON DELETE CASCADE;Source : | Last Update : Tue, 06 Sep 22
Answered by : rui-fj2brd3pa284
There could be a couple of things going one here. Here are some things to look for:
Do the data types of each field between the tables match?
Are both both tables using the same MySQL engine?Source : https://stackoverflow.com/questions/20585592/cant-create-foreign-key-constraint-in-mysql | Last Update : Sat, 12 Mar 22