Download CHAPTER 1: THE DATABASE ENVIRONMENT

UNIVERSITY OF PANGASINAN-PEN
COLLEGE OF INFORMATION TECHNOLOGY EDUCATION
ITE 049 DATABASE MANAGEMENT SYSTEM 1
A.Y. 2014 - 2015; 1st Semester
LECTURE NOTES I
CHAPTER 1: THE DATABASE ENVIRONMENT
DATABASE
 An organized collection of logically related data. A database may be of any size and complexity.
o by organized, data are well structured so as to be easily stored, manipulated & retrieved by users.
o by related, data describe a domain of interest to a group of users and that the user can use the
data to answer questions concerning that domain.
DATA


referred to known facts that could be recorded on a computer media.
Facts, text, graphics, images, sound and video segments that have meaning in the users’ environment.
o Structured:
numbers, text, dates
o Unstructured: images, video, documents
THE DATA PROCESSING CYCLE
In computing, data pertains to a raw aggregate of facts, which when subjected to processing become
meaningful. This processed data is referred to as information. Information is organized data and presented in a
manner that has additional meaning and value beyond the data itself.
Typically, this data conversion is termed IPO which stands for input-process-output. Initially, data is fed
as input for processing (1) and information is produced (2) as the output. Processed data may be saved or
stored in a storage media such as a hard disk (3), and retrieved back for future or later use as an input for
succeeding operations (4). This means then that input may either be data or information. In all cases, however,
outputs of processing are referred to as information. During processing, some “old” data stored previously may
be needed to complement or complete the operation at hand (5) and processed results may be written back
to update the “old” data (6).
INFORMATION
 Data that have been processed in such a way as to increase knowledge of the person who uses the
data.
METADATA
 data that describes the properties and context of user data.
Figure 2. Data in Context
Figure 2. Summarized Data
Context helps users understand data
Graphical displays turn data into useful information that
managers can use for decision making and interpretation
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UNIVERSITY OF PANGASINAN-PEN
COLLEGE OF INFORMATION TECHNOLOGY EDUCATION
ITE 049 DATABASE MANAGEMENT SYSTEM 1
A.Y. 2014 - 2015; 1st Semester
LECTURE NOTES I
Descriptions of the properties or characteristics of the data, including data types, field sizes,
allowable values, and data context
DISADVANTAGES OF FILE PROCESSING SYSTEM
1. Program-Data Dependence
o All programs maintain metadata for each file they use
2. Duplication of Data
o Different systems/programs have separate copies of the same data
3. Limited Data Sharing
o No centralized control of data
4. Lengthy Development Times
o Programmers must design their own file formats
5. Excessive Program Maintenance
o 80% of information systems budget
Problems with Data Dependency
 Each application programmer must maintain his/her own data
 Each application program needs to include code for the metadata of each file
 Each application program must have its own processing routines for reading, inserting, updating, and
deleting data
 Lack of coordination and central control
Problems with Data Redundancy
 Waste of space to have duplicate data
 Causes more maintenance headaches
 The biggest problem:
o Data changes in one file could cause inconsistencies
o Compromises in data integrity
SOLUTION:
The DATABASE Approach
 Central repository of shared data
 Data is managed by a controlling agent
 Stored in a standardized, convenient form
 Requires a Database Management System (DBMS)
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UNIVERSITY OF PANGASINAN-PEN
COLLEGE OF INFORMATION TECHNOLOGY EDUCATION
ITE 049 DATABASE MANAGEMENT SYSTEM 1
A.Y. 2014 - 2015; 1st Semester
LECTURE NOTES I
DATABASE MANAGEMENT SYSTEM
 A software system that is used to create, maintain, and provide controlled access to user databases
DBMS manages data resources like an operating system manages hardware resources
ADVANTAGES OF THE DATABASE APPROACH
1. Program-data independence
2. Minimal data redundancy
3. Improved data consistency
4. Improved data sharing
5. Increased productivity & application development
6. Enforcement of standards
7. Improved data quality
8. Improved data accessibility and responsive/ness
9. Reduced program maintenance
Costs and Risks of the Database Approach
1. New, specialized personnel
2. Installation and management cost and complexity
3. Conversion costs
4. Need for explicit backup and recovery
5. Organizational conflict
Relational Databases
 Database technology involving tables (relations) representing entities and primary/foreign keys
representing relationships
Database Applications
 Application programs that is used to perform database activities for database users.
o Create:
Add new data to the database
o Read:
Read current database data
o Update: Modify current database data
o Delete:
Remove current data from the database.
RANGE OF DATABASE APPLICATION
1. Personal Database (1)
 Designed to support one user. Personal databases have long resided on personal computers
(PC’s), including laptops.
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UNIVERSITY OF PANGASINAN-PEN
COLLEGE OF INFORMATION TECHNOLOGY EDUCATION
ITE 049 DATABASE MANAGEMENT SYSTEM 1
A.Y. 2014 - 2015; 1st Semester
LECTURE NOTES I
2. Workgroup Database (5-25)
 Designed to support the collaborative efforts of such team.
Workgroup
 relatively small team of people who collaborate on the same project or application.
Database Server  central storage device, connected to the network
Figure 3. Workgroup database with wireless
3. Department Database (25-100)
 Designed to support various functional and activities on a department
Department
 a functional unit within an organization.
4. Enterprise Database (>100)
 One whose scope is the entire organization or enterprise.
ERP(Enterprise Resource Planning)  are software applications that provide the data necessary for the enterprise
to examine and manage its activities.
Data Warehouse
 an integrated decision support whose content is derived from the various operational
database.
Figure 4 An enterprise data warehouse
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UNIVERSITY OF PANGASINAN-PEN
COLLEGE OF INFORMATION TECHNOLOGY EDUCATION
ITE 049 DATABASE MANAGEMENT SYSTEM 1
A.Y. 2014 - 2015; 1st Semester
LECTURE NOTES I
5. Web enabled (>1000)
 INTERNET
 Worldwide network that connects users of multiple platforms easily.
 INTRANET
 Use of internet protocol to establish access to company data and information that is limited to
organization.
 EXTRANET
 Use of internet protocol to establish access to company data and information by the
company’s customers & suppliers.
COMPONENTS OF THE DATABASE ENVIRONMENT
1. CASE (Computer-Aided Software Engineering)Tools
 An automated tools use to design databases and application program.
 System developers often use this tools for system requirements analysis and program design.
2. Repository
 Centralized knowledge base for all data definitions, data relationships, report formats, and
other system components.
3. Database Management System (DBMS)
 Commercial software system used to define, create, maintain, and provide controlled access to
the database and repository.
4. Database
 An organized collection of logically related data, usually designed to meet the information
needs of multiple users in an organization.
5. Application Programs
 Are used to create and maintain the database and provide information to users.
6. User Interface
 text and graphical displays by which users interact with various system components, such as
CASE tools, application programs, the DBMS & repository.
7. Data/Database Administrators
 personnel responsible for maintaining the database
8. System Developers
 personnel responsible for designing databases and software
9. End Users
 people who uses the applications and databases.
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