Cascade functionality..

[Allijah]

hi there, I've found online describing how the CASCADE functionality of foreign keys will help maintain referential integrity for my DB.

here is the batch file I run which outlines the exercise. my output from running that batch. I'm running mysql version 4.1.21 over a mapped drive. My variable FOREIGN_KEY_CHECKS is set to 1. so I assume that's correct.

there is one row missing in the final table

[START BATCH (gen.txt)]

drop table if exists genre;

create table genre (
id serial PRIMARY KEY UNIQUE,
name varchar(16));

drop table if exists subgenre;

create table subgenre(
name varchar(16),
genre_id int REFERENCES genre(id) ON UPDATE CASCADE);

insert into genre(name) values('Rock');
insert into genre(name) values('Jazz');

insert into subgenre values('Metal', '1');
insert into subgenre values('Bebop', -- This message may have been cut off and the rest will only be shown to members. To become a member, click here --

[Ivy]

Try the following:

Put ENGINE=InnoDB on the end of your CREATE TABLE statements to request the InnoDB engine.

Do a SHOW CREATE TABLE <tablename> to verify that the InnoDB engine was selected, since MySQL will silently substitute MyISAM if InnoDB support is not available. -- This message may have been cut off and the rest will only be shown to members. To become a member, click here --