Database Management System Adisak Intana Lecturer Chapter 1: Introduction

Introduction to Database System 2 Table Contents Enterprize, data and information File processing system Database system DBA Query Languages

Introduction to Database System 3 Enterprize, data and information u An enterprise is a generic term for any resonably self-contained commercial, scientific, technical, or other organization. u Examples of enterprize : university, department store, hospital, sale product company

Introduction to Database System 4 Enterprize, data and information (Cont.) Business areas and application systems Supplier Order System Sale Product Company Marketi ng Depart ment Person nel Depart ment IS Depart ment Customer Order System Payro ll Syste m Applications Developmen t System Accoun ting Depart ment Accou nting System

Introduction to Database System 5 Enterprize, data and information (Cont.) Application systems and application programs Supplier Order System Application systems Customer Order System Payro ll Syste m Applications Developmen t System Accou nting System Application programs

Introduction to Database System 6 Enterprize, data and information (Cont.) Data Processing Data processing Application program & data Information

Introduction to Database System 7 Enterprize, data and information (Cont.) Data and information Da ta Decisio n Convers ion Reque st Interpret ation Knowle dge Informati on

Introduction to Database System 8 Enterprize, data and information (Cont.) Data and information Da ta Decisio n Convers ion Reque st Interpret ation Knowle dge Informati on

Introduction to Database System 9 Often the terms data and information are used interchangeably, but they are different. u Data are raw, unsummarized, and unanalyzed facts. u Information is data that have been processed into meaningful form. Data and information

Introduction to Database System 10 Information system An information system is a system that supplies the information needed by an organization or enterprise.

Introduction to Database System 11 Data processing Most application programs need to store data that can be retrieved later. Most programming languages have the ability to create and store data in separate files.

Introduction to Database System 12 File system ข้อมูลจำนวนไม่มาก อาจสามารถเก็บไว้ในแฟ้ม เอกสาร แยกเป็นเรื่องๆ โดยเนื้อหาที่จัดเก็บในแต่ ละแฟ้มจะเป็นข้อมูลที่เกี่ยวข้องกัน เช่น – แฟ้มข้อมูลคนไข้ของโรงพยาบาล ประกอบด้วยข้อมูล คนไข้ เช่น ชื่อ สกุล ที่อยู่ ประวัติการรักษา เป็นต้น แฟ้ม แต่ละแฟ้มเก็บข้อมูลคนไข้หนึ่งคน – แฟ้มข้อมูลพนักงานขององค์กร ประกอบด้วย ประวัติ พื้นฐานของบุคลากร ประวัติการทำงาน เงินเดือน เป็นต้น การเก็บแฟ้มข้อมูลพนักงานอาจจะมีการแยกกลุ่ม แฟ้มข้อมูลไปตามแผนก และเรียงลำดับแฟ้มตามชื่อ สกุลของพนักงานเพื่อความสะดวกในการสืบค้นข้อมูล

Introduction to Database System 13 File system (Cont.) การเก็บข้อมูลด้วยคอมพิวเตอร์ในช่วงแรกเริ่ม เป็น การเลียนแบบการทำงานด้วยมือ นั่นคือนำเอกสาร ต่างๆมาพิมพ์เก็บไว้ในคอมพิวเตอร์ และมีการ จัดเก็บแยกเป็นแฟ้มข้อมูล แต่ละแฟ้มข้อมูลเก็บ ข้อมูล 1 เรื่อง เรียกว่า “ ระบบแฟ้มข้อมูล ” (File system)

Introduction to Database System 14 File System (Cont.)

Introduction to Database System 15 File system (Cont.)

Introduction to Database System 16 Drawback of file system Uncontrolled duplication of data (data redundancy) p Wastes space p Hard to update all files p Inconsistent data

Introduction to Database System 17 Sales Department Sales Person file PersonalDepartment Employee file Drawback of file system (Cont.)

Introduction to Database System 18 Sales Department Sales Person file PersonalDepartment Employee file Hard to update Wastes space Inconsistent Drawback of file system (Cont.)

Introduction to Database System 19 Drawback of file system (Cont.) Inflexibility p Hard to access unexpected information p Excessive programs maintenance

Introduction to Database System 20 Hard to access unexpected information Sales Department Sales Person file Drawback of file system (Cont.)

Introduction to Database System 21 Drawback of file system (Cont.) Limited data sharing p Same data is scattered in various files which may be in different format. p Difficult to use data from these existing files for new programs

Introduction to Database System 22 Sales Department Sales Person file PersonalDepartment Employee file Integer Character Same data may be in Different format Difficult to use data from these existing files for new programs Drawback of file system (Cont.)

Introduction to Database System 23 Drawback of file system (Cont.) Data dependence problem p Application programs are dependent upon the structure of files and data structures they processed. p Changes of files and/or data structures result in recompiling the application programs.

Introduction to Database System 24 Database system Database CUSTOMER EMPLOYEE SALE Staff recruitment system Customers’ orders system Sales accounting system Sales Department Personal Department

Introduction to Database System 25 Database Processing The main problem of database processing is security of data in the database is.

Introduction to Database System 26 Database system Database CUSTOMER EMPLOYEE SALE Staff recruitment system Customers’ orders system Sales accounting system Sales Department Personal Department DBMS

Introduction to Database System 27 Database Processing using DBMS Not allow any application program directly access the database.

Introduction to Database System 28 Database Administration Resources in database environment are : Resources in database environment are : – Database – DBMS – Related software Administering these resources is the responsibility of the database administrator (DBA) Administering these resources is the responsibility of the database administrator (DBA)

Introduction to Database System 29 Database administrator Responsible for all the activities of the database system environment. Has a good understanding of the enterprise’s information resources and needs. Has a good understanding of the enterprise’s information resources and needs. Has a good knowledge and understanding of database technology. Has a good knowledge and understanding of database technology.

Introduction to Database System 30 Database administrator's duties : Database administrator's duties : – Design and define of database schema and subschema – Define storage structure and access method – Modify schema and physical database organization – Define authorization and database security – Define integrity constraints Database administrator

Introduction to Database System 31 Database administrator's duties (cont.) : – Ensure data availability and recovery from failures – Monitoring performance and responding to changes in requirements – Tuning database to ensure adequate performance as user requirements change. – Provide effective use of DBMS – Acting as liaison with users Database administrator

Introduction to Database System 32 Classification and functions of DBAs Database designer – Collects and identifies the data and their relationships to be stored in the database. – Design the conceptul, logical, and physical database structure.

Introduction to Database System 33 Database manager – Determines and grants authorized users to access the database. – Defines view of the database to be manipulated by authorized users. – Sets integrity constraints of business ruls for security, privacy, and integrity control. – Provides education and training of database technology to users. Classification and functions of DBAs

Introduction to Database System 34 DBMS administrator – Applies appropriate physical database structure. – Provides effective use of DBMS. – Provides any available tools that could make the users’ community more productive. Classification and functions of DBAs

Introduction to Database System 35 Accessing database Programm er/DBA Programm er/ Knowled worker/ End- users User interface High-level tools Database management system System analyst

Introduction to Database System 36 Data Definition Language : DDL – CREATE – ALTER – DROP Data Manipulation Language : DML – SELECT – INSERT – UPDATE – DELETE Query Languages

Introduction to Database System 37 Data Control Language : DCL – GRANT – REVOKE – COMMIT – ROLLBACK Query Languages