Question

I am creating 3 subclass table, other 2 is done and work normally but I get this error(1064) when I enter the following code for the last table:

mysql> CREATE TABLE foreign (
    -> account_no VARCHAR(16) NOT NULL,
    -> foreign_id VARCHAR(16) NOT NULL,
    -> TYPE CHAR(4) DEFAULT 'FORE' NOT NULL
    -> CHECK ( TYPE = 'FORE'),
    -> currency_TYPE CHAR(3) NOT NULL
    -> CHECK ( currency_TYPE IN ('EUR','USD','HKD')),
    -> balance DECIMAL(16,2),
    -> PRIMARY KEY(account_no, foreign_id),
    -> FOREIGN KEY(account_no, TYPE)
    -> ON UPDATE CASCADE
    -> ON DELETE CASCADE);

the error message informs me that between foreign( account_no VARCHAR(16) NOT NULL, foreign_id VARCHAR(16) NOT NULL, TYPE gets wrong syntax, but I can’t find it, is there anything wrong?

Answer 1

For FOREIGN KEY(account_no, TYPE) you need to give Reference columns

Example

CREATE TABLE parent (id INT NOT NULL,
                 PRIMARY KEY (id)
  ) 
 CREATE TABLE child (id INT, parent_id INT,
                INDEX par_ind (parent_id),
                FOREIGN KEY (parent_id) REFERENCES parent(id)
                  ON DELETE CASCADE
   )