Introduction to Database

1
Introduction to Database

• CIS458.101
• Chapter 1

2
Database System

• The most important development in the field of
  software engineering.
• Databases serve as the foundation for
  considerable progress in the basic science fields
  ranging from computing to biology.

3
Introduction

• Database
• A shared collection of logically related data,
  and description of this data, designed to meet
  the information needs of an organization.
• DBMS (Database Management System)
• The software system that enables users to define,
  create, maintain and control access to the
  database.
• Database application
• A computer program that interacts with the
  database by issuing an appropriate request to the
  DBMS.

4
Examples of Databases

• Supermarket
• Inventory
• Customer Service
• Credit Card
• Booking a ticket at the travel agents
• Using the local library
• University

5
Traditional File-Based Systems

• Each program defines and manages its own data.
• Separation and isolation of data
• Duplication of data
• Data dependence
• Incompatibility of files
• Fixed queries of application program

6
Database Approach

• A shared collection of logically related data,
  and a description of this data, designed to meet
  the information needs of an organization.
• System catalog (data dictionary)
• Program-data independence.

7
File-Based System
File handling routines
Data entry report
File definition
Sales Files
8
The Database Management System (DBMS)

• A software system that enables users to define,
  create, maintain, and control access to the
  database.
• Data Definition Language(DDL)
• Data Manipulation Language (DML)
• Structured Query Language (SQL)
• Views
• Level of security, customization, provide
  consistent structure

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Components of the DBMS Environment

• Hardware
• Client-server architecture
• Backend, front end
• Software
• DBMS, application programs, SQL
• Data
• Operational data, meta data
• Procedure
• Instructions and rules
• People

10
Roles in the Database Environment

• Data Administrator (DA)
• Responsible for the management of the data
  resource including database planning, development
  and maintenance of standards, policies, and
  procedures, and conceptual/logical database
  design.
• Database Administrator (DBA)-more technical
• Responsible for the physical realization of the
  database, including physical database design and
  implementation, security and integrity of the
  application users.

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Roles in the Database Environment (2)

• Database Designer
• Logical database designer
• Identifying the data, relationship between the
  data, and the constraints on the data.
• Business rules.
• Physical database designer
• Mapping the logical database design into a set
  of tables and integrity constraints.
• Selecting specific storage structures
• Designing security measures required on the data

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Roles in the Database Environment (3)

• Application Developer
• Provide the required functionality for the
  end-users.
• End-Users
• Naïve users
• Sophisticated users.

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Data Redundancy
14
Advantages of DBMS

• Control of data redundancy
• Data consistency
• More information from the same amount of data
• Sharing of data
• Improved data integrity
• Improved security
• Enforcement of standards

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Advantages of DBMS (2)

• Economy of scale
• Balance of confliction requirements
• Improved data accessibility and responsiveness
• Increased productivity
• Improved maintenance through data independence
• Increased concurrency
• Improved backup and recovery services

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Disadvantages of DBMS

• Complexity
• Size
• Cost of DBMS
• Additional hardware costs
• Cost of conversion
• Performance
• Higher impact of a failure

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History of DBMS

• Apollo moon-landing project (1960s)
• GUAM (Generalized Update Access Method)
• Hierarchical structure
• IMS (Information Management System) (mid 1960s)
• Serial storage
• device (Tape recorder)
• IDS (Integrated Data Store) (mid 1960s)
• Network DBMS
• CODASYL (Conference on Data Systems Languages)

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History of DBMS

• DBTG (Data Base Task Group) 1967
• Relational Model E. F. Codd, 1970
• R
• SQL
• DB2, SQL/DS, Oracle
• INGRES II, Informix, Access, FoxPro, Paradox,
  Interbase, and RBase
• ER model Chen, 1979
• Semantic data modeling
• Object-Oriented DBMS, Object-Relational DBMS