1. CS 1431 USER-ORIENTED DESCRIPTION OF A DATABASE MANAGEMENT SYSTEM

2. CS 1432 TWO TYPES OF DATABASES  (1) STATIC DATABASE Describes Entities existing in the system through their properties. Describes Relationships existing between entities. Basically “static”; changes in the entities properties and relationships require “protected” operations. (2) DYNAMIC DATABASE Describes dynamic Entities and Relationships. Usually constructed as “simulation systems”. Dynamic behavior and commands are inherent to the system.

3. CS 1433 GENERAL USER ORIENTED DESCRIPTION OF DBMS A Database Management System (DBMS) consists of: (1) Database (2) Data Definition Language (DDL) (3) Query Language (QL) (4) Data Manipulation Language (DML) (5) “System”

4. CS 1434 THE DATABASE A Database may be defined as a collection of “related”, “stripped down”, “declarative” statements arranged in a tabular form. Example Starting with the declarative statements: - John Smith is an employee earning $35,000/year. - Paula Jones is an employee earning $40,000/year. - Peters is an employee working in the toy department and earning $30,000/year. - Paula Jones is the manager of the toy department. - John Smith works in the toy department. - Peters works in the toy department.

5. CS 1435 SOME ACTUAL DATABASE INSTANCES - We would construct the following two databases: First NameLast NameDepartmentSalary JohnSmithtoy35000 PaulaJonestoy40000 Peterstoy30000 Managers SupervisorSupervisees JonesSmith JonesPeters Employee

6. CS 1436 Permits users to state imperative commands that yield (upon execution) database Schemas and Instances. Example: (1) to create the schema EMPLOYEE: CREATE TABLE EMPLOYEE (fname: string, lname: string, department: string, salary: integer) (2) to create the instance of EMPLOYEE shown in slide 5 above: INSERT EMPLOYEE (,, ) DATA DEFINITION LANGUAGE

7. CS 1437 QUERY LANGUAGE (QL) Permits users to state queries against the database. Example SELECT lname, salary FROM Employee WHERE salary > 35000

8. CS 1438 DATA MANIPULATION LANGUAGE (DML) Permits users to manipulate (i. e. to modify) the database. Example ALTER TABLE employee ADD COLUMN ssn INTEGER N.B. The DDL and DML are often combined into a single language.

9. CS 1439 THE SYSTEM The software and hardware which permit users to define, construct, query and modify the database.