Adding foreign key in MySQL

Adding foreign key in MySQL This sql sintax can create link betwen key in some tables. Please used in InnoDB only. Here the code: ALTER TABLE child_table_name ADD FOREIGN KEY (P_ID) REFERENCES parent_table_name (P_ID) #example: ALTER TABLE member_detail ADD FOREIGN KEY (username) REFERENCES member (username) #foreign key will be deleted/updated if primary key deleted/updated ON DELETE CASCADE ON UPDATE CASCADE #parent will not be deleted if any child row exist ON DELETE RESTRICT #The script will be: ALTER TABLE member_detail ADD...

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