[curtiss]

Are you using PHPMyAdmin to administer the database, or do they have some other tool?

You should set item number to primary key. Do not set any others to primary key, as none of the other fields will be unique. The primary key has to be unique. In the case where none of your columns will be totally unique, then you would add a unique index (usually an auto_increment number of some sort) as your ID.

I would go ahead an index all 4 columns, as you will be searching the database from each of the 4 columns. Do not set any of them to unique, as the ItemNumber is the only column that will contain completely unique entries.