Relational Database Schemas

In this lesson, we will discuss the basic concepts behind relational database schemas.

Relational database schemas

A relational database schema S is a set of relation schemas S = {R1_1, R2_2, … , Rm_m} and a set of integrity constraints IC. A relational database state DB of S is a set of relation states DB = {r1_1, r2_2, … , rm_m} such that each ri_i is a state of Ri_i. The figure below shows a relational database schema that we call COMPANY = {EMPLOYEE, DEPARTMENT, DEPT_LOCATIONS, PROJECT, DEPENDENT}. In each relation schema, the underlined attribute represents the primary key.

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