This chapter dealt with technique--the technique of creating an orderly data layout using multiple tables. Acquiring this skill takes practice. Expect to improve your first table layouts many times.
Good data layout can make your job easier. Bad data layout can turn queries into a nightmare. As you create your first real-world tables, you will learn to identify good and bad data designs. Continually review your table structures and refer to this chapter again for ideas. Do not be afraid to redesign everything. Redesign is hard, but when it is done properly, queries become easier to craft.
Relational databases excel in their ability to relate and compare data. Tables can be joined and analyzed in ways you might never have anticipated. With good data layout and the power of SQL, you can retrieve an unlimited amount of information from your database.