SQL

mysql modify foreign key

-- 2 Step process
ALTER TABLE tbl_name_1 DROP FOREIGN KEY fk_name;
ALTER TABLE tbl_name_1 ADD FOREIGN KEY fk_name(fk_col)
            REFERENCES tbl_name_2(pk_name) ON DELETE RESTRICT;


-- Use to find the name of the FOREIGN KEY 
SHOW CREATE TABLE tbl_name;

alter table add foreign key mysql

ALTER TABLE orders
ADD 
FOREIGN KEY (user_id) REFERENCES users(id) ON DELETE CASCADE; 

alter table add column and foreign key mysql

ALTER TABLE database.table
  ADD COLUMN columnname INT DEFAULT(1),
  ADD FOREIGN KEY fk_name(fk_column) REFERENCES reftable(refcolumn) ON DELETE CASCADE;

mysql alter add foreign key

ALTER TABLE ordenes ADD ticket VARCHAR(50) NOT NULL;
ALTER TABLE ordenes ADD CONSTRAINT fk_ticket FOREIGN KEY (ticket) REFERENCES tickets(ticket);
// I'm Horrible Hyena

mysql alter add foreign key

ALTER TABLE ordenes ADD ticket VARCHAR(50) NOT NULL;
ALTER TABLE ordenes ADD CONSTRAINT fk_ticket FOREIGN KEY (ticket) REFERENCES tickets(ticket);

add column mysql with foreign key

ALTER TABLE `TABLE_NAME`
ADD COLUMN `COLUMN_NAME` BIGINT(20) UNSIGNED NULL DEFAULT NULL AFTER `AFTER_COLUMN_NAME`, 
ADD FOREIGN KEY `FOREIGN_RELATION_NAME`(`COLUMN_NAME`) REFERENCES `FOREIGN_TABLE`(`FOREIGN_COLUMN`)  ON UPDATE SET NULL ON DELETE SET NULL