When you're optimizing a data model for good performance, "thinner is better" is a philosophy that you can apply to your database tables. In this context, "thinner" relates to the number of columns in a table and the maximum byte count in one row (aka row size). Keep in mind that one of the more expensive operations in a database environment is disk I/O—transferring data from disk to cache and back again. All computations, all retrievals, even the simplest queries (e.g., SELECT * FROM pubs....