Question

I have created multiple tables in MySQL, yet data in some fields in one or more table should exist in other tables. I know that this can be created by adding foreign key to the table.

I would like to know how this can be done.

Please note that on deletion of any record all linked should NOT be deleted … the value can be changed to null. I’ll manage it in other way.

PS: I just need the code to do this.

Answer 1

CREATE TABLE other (
  id unsigned integer auto_increment primary key
  ,field1 varchar(100) not null) ENGINE = InnoDB;

CREATE TABLE example (
  id unsigned integer auto_increment primary key
  ,field1 varchar(100) not null
  ,other_id unsigned integer
  ,FOREIGN KEY FK_example_other_table (foreign_id) REFERENCES other(id) 
   ON DELETE RESTRICT
   ON UPDATE CASCADE ) ENGINE = InnoDB;

See: http://dev.mysql.com/doc/refman/5.1/en/create-table.html