- A fact in itself is nothing. It is valuable only for the idea attached to it, or for the proof which it furnishes.
- —CLAUDE BERNARD
Topics Covered in This Chapter
- Why Keys Are Important
- Establishing Keys for Each Table
- Table-Level Integrity
- Reviewing the Initial Table Structures
- Case Study
- Review Questions
By now you’ve identified all the subjects that the database will track and defined the table structures that will represent those subjects. Furthermore, you’ve put the structures through a screening process to control their makeup and quality. In this next stage of the database design process, you’ll begin the task of assigning keys to each table. You’ll soon learn that there are different types of keys, and each plays a particular role within the database structure. All but one key is assigned during this stage; you’ll assign the remaining key later (in Chapter 10, “Table Relationships”) as you establish relationships between tables.