cannot insert

i just don't understand why i cannot insert some form data into MySQL INNODB table, plz help!

insert statement$q = "INSERT INTO books VALUES ('$title', '$author')";
return mysql_query($q, $this->connection);
first tableCREATE TABLE books (
title varchar(90),
author varchar(90)
) TYPE=INNODB;

no problem at all insert form data into this table, but when i change the table to CREATE TABLE books (
book_id INT NOT NULL AUTO_INCREMENT PRIMARY KEY,
title varchar(90),
author varchar(90)
) TYPE=INNODB;

i cant insert nothing, very strange!
there's no foreign key involved, just a single table. what's the problem?

thx very much

if you're not putting values in all the columns, you need to specify which ones you want- how would you expect mysql to know otherwise?
i.e your query should be:

$q = "INSERT INTO books (title,author) VALUES ('$title', '$author')";

the alternative is to pass NULL as the first column, mysql will then do it's autoincrement magic, and you'll get the same result, i.e.

$q = "INSERT INTO books VALUES (NULL,'$title', '$author')";


For the sake of clarity, the first method is preferable, it's much easier to see what you're doing.

thanks Gjay, you are right to the point, i change the code you mentioned first, and it works now! thanks again!