According to the relational model, data in a relational database is stored in relations, which are perceived by the user as tables. Each relation is composed of tuples (records) and attributes (fields). Figure 3.6 shows a typical table structure.
Figure 3.6. A typical table structure.
Tables are the chief structures in the database and each table always represents a single, specific subject. The logical order of records and fields within a table is of absolutely no importance, and every table contains at least one field—known as a primary key—that uniquely identifies each of its records. (In Figure 3.6 ...