MySQL error cannot add foreign key constraint

Question

what is wrong?

mysql> create table price(
    -> p_code char(1) not null,
    -> p_description varchar(20),
    -> p_rentfee decimal(2,2) not nul         


        

Answer 1

1. The referenced column price.p_code must be unique (primary or unique key need to be created).
2. Both tables must be InnoDb tables, use ENGINE = INNODB in CREATE TABLE statement.