CEVAP:

The relational database model is the most widely used database structure. In the relational model, all data are stored in the form simple two-dimensional tables (p:48, Figure 2.7).

In this database, “Departments Table” holds records of departments represented with four fields. Here, department number is the primary key. All the rows (records) must have a unique department name.

Each row of “Projects Table” represents a project. The columns in the tables are fields. “Department Number” column exists in both of the Department table and the Projects tables. With the aim of this column, the two tables can be joined together. That is, “Department Number” field, which is a primary key in the Department Table, is called foreign key in Projects table. A foreign key is used to link two tables.