It will not let you because you have a Primary Key and a Unique key.
I was curious if that was what you really wanted.
You stated you wanted 2 Primary keys, and you can have one.
A primary key has to be unique.
You can also create a unique key across different values or make another field be Unique, which we did
PRIMARY KEY (album_id) ,
UNIQUE KEY `aid` (`artist_id`)
So you want a KEY (assuming you plan on needing it) and a Primary key
drop table album;
CREATE TABLE album (
album_id INT (4) NOT NULL AUTO_INCREMENT,
artist_id INT(5) NOT NULL,
album_name varchar(128) DEFAULT NULL,
PRIMARY KEY (album_id) ,
KEY `aid` (`artist_id`)
);
This will allow you to enter 1 album ID and more than 1 artist id.
Just trying to help....
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