1. CHAPTER 1: DATABASE ENVIRONMENT
Chapter Objectives
At the end of the chapter, you should be able to:
 define the basic terminologies;
 know the differences between a file processing approach and a database approach;
 list the components of database environment.
Essential Reading
Modem Database Management (4th Edition), Fred R. McFadden & Jeffrey A. Hoffer (1994),
Benjamin/Cummings. [Chapter 1, page 5 - 30]
Useful Websites to learn Database and Programming:
http://erwinglobio.wix.com/ittraining
http://ittrainingsolutions.webs.com/
http://erwinglobio.sulit.com.ph/
http://erwinglobio.multiply.com/
Prof. Erwin M. Globio, MSIT 1-1

2. DB212 CHAPTER 1: DATABASE ENVIRONMENT
1.1 Basic Terminologies
DATA INFORMATION
PROCESS
Data are facts concerning things such as people, objects or events. For example, an invoice
which consists of data, order-no, customer particulars etc. can be considered as data.
Information is data that have been processed and presented in a form suitable for human
interpretation, often with the purpose of revealing trends or patterns.
To convert data into information, we need to process the data. The process involves
acquisition, storage, manipulation, retrieval and distribution.
A database is a shared collection of logically related data, designed to meet the information
needs of multiple users in an organization.
DATABASE
file
FILES
record 1
record 2 DATA
record 3
………
There are two generic database system designs: centralized and distributed.
With a centralized database, all data are located at a single site.
 Advantage
 Provide greater control over accessing and updating data
 Disadvantage
 Vulnerable to failure
 Examples: Personal Computer Database, Central Computer Database, Client/Server
Databases
1-2 Prof. Erwin M. Globio, MSIT

3. DB212 CHAPTER 1: DATABASE ENVIRONMENT
A distributed database is a single logical database that is spread physically across computers
in multiple locations.
Homogeneous Database need to comprise of the following conditions:
 The compatible operating systems used at each location are the same or highly
compatible.
 The data models used at each location are the same.
 The DBMS used at each location are the same or highly compatible.
 The data at the various locations have common definitions and formats.
Heterogeneous Databases means different computers and operating systems, different data
models, different DBMS may be possible.
1.2 File Processing Approach
File processing approach is a traditional approach to information system design focuses on the
data processing needs of individual departments in the organization.
1.2.1 Disadvantages of File Processing Approach
 Uncontrolled Redundancy
 In file processing system, each application has its own files, an approach that
inevitably leads to a high level of data redundancy (that is, duplication of data). There
are several disadvantages to recording the same data item in multiple files:
 Valuable storage space is wasted
 The same data may have to be input several times to update all occurrences of a data
item
 Inconsistencies (or various versions) often result
 Inconsistent Data
 When the same data are stored in multiple locations, inconsistencies are inevitable.
Inconsistencies in stored data are one of the most common sources of errors in
computer applications. They lead to inconsistent documents and reports and
undermine the confidence of users in the integrity of the information systems.
 Inflexibility
 A file processing system resembles a mass-production facility. It produces numerous
documents and reports routinely and efficiently, provided that these outputs were
anticipated in the original design of the system. Such systems, however , are often
quite inflexible and cannot easily respond to requests for a new or redesigned
product. This often leads to considerable frustration on the part of the users, who
cannot understand why the computer system cannot give them information in a new
format when they know it exists in the applications files.
Prof. Erwin M. Globio, MSIT 1-3

4. DB212 CHAPTER 1: DATABASE ENVIRONMENT
 Limited Data
 Sharing with the traditional applications approach, each application has its own
private files, and users have little opportunity to share data outside of their own
applications. The consequences of such limited data sharing may be:
 The same data may have to be entered several times to update files with duplicate
data.
 In developing new applications, the designer often cannot (or does) exploit data
containing in existing files; instead new files are designed that duplicate much of the
existing data.
 Poor Enforcement of Standards
Unfortunately, data standards (i.e. data names, formats and access restrictions) are
difficult to make known and enforce in a traditional file processing environment, mainly
because the responsibility for system design and operation has been decentralized. Two
types of inconsistencies may result from poor enforcement of standards: Synonyms and
homonyms. A synonym results when two different names are used for the same data item
- For example, student number and matriculation number. A homonym is a single name
that is used for two different data items - for example, in a bank the term balance might be
used to designate a checking account balance in one department and a savings account
balance in a different department.
 Excessive Program Maintenance
 In file processing systems, descriptions of files, records, and data items are embedded
within individual application programs. Therefore, any modification to a data (such
as change of data name, data format, or method of access) requires that the program
(or programs) also be modified.
1.3 Database Approach
The database approach emphasizes the integration and sharing of data across the organization.
1.3.1 Data-driven vs Process-driven Design
In file processing system, a process-driven approach has traditionally been used to design
information system.
With the process-driven approach, organizational processes are first identified and analyzed.
Processes and data flows between processes are described using tools such as DFD. Designers
then work backward from the required to convert inputs into outputs. Design of data files are a
by-product of process design.
With database approach, information systems professional discovered that a data-driven
approach is often preferable. In the data-driven approach, entities that the organization must
manage are focuses on first. Attributes and relationships of those entities are identified. After
creating suitable models of the data structures and related business rules, designers develop
the applications required to manage the data.
1-4 Prof. Erwin M. Globio, MSIT

5. DB212 CHAPTER 1: DATABASE ENVIRONMENT
The best is to strike a balance between data-driven design and process-driven design.
Requirement Analysis
Requirement Analysis Requirement Analysis
Process Design Database Design
Data Design Process Design
Implementation Implementation
Process-driven Design Data-driven Design
1.3.2 Benefits of the Database Approach
 Minimal Data Redundancy
With the database approach, data files are integrated into a single, logical structure. We
are not suggesting all redundancy is controlled. It is designed into the system to improve
performances (or provide some other benefits), and the system is (or should be) aware of
redundancy.
 Consistency of Data
By controlling data redundancy, we greatly reduce the opportunities for inconsistency.
For example, if each address is stored only once, we cannot have disagreement on the
stored values. When controlled redundancy is permitted in the database, the database
system itself should enforce consistency by updating each occurrence of a data item when
a change occurs.
 Integration of Data
In a database, data are organized into a single, logical structure, with logical relationships
defined between associated data entities. This makes it easy for users to relate one item of
data to another.
 Sharing of Data
Most database systems today permit multiple users to share a database concurrently,
although certain restrictions are imposed such that each user would be able to view a
subset of the conceptual database model.
 Ease of Application Development
A major advantage of the database is that it greatly reduces the cost and time for
developing new business applications as programmer is relieved from the burden of
designing, building, and maintaining master files. In a database system, data are
independent of the application programs that use them. Within limits, either data or the
application programs that use the data can be changed without necessitating a change in
the other factor.
Prof. Erwin M. Globio, MSIT 1-5

6. DB212 CHAPTER 1: DATABASE ENVIRONMENT
1.3.3 Costs of the Database Approach
 New, Specialized Personnel
Frequently, organizations that adopt the database approach or purchase a database
management system (DBMS) need to hire train individuals to maintain the new database
software, develop and enforce new programming standards, design databases to achieve
the highest possible performance, and manage the staff of new people.
 Need for Explicit Backup
Minimal data redundancy, with all its associated benefits, may also fail to provide backup
copies of data. Such backup or independently produced copies are helpful in restoring
damaged files and in providing validity checks on crucial data. To ensure that data are
accurate and available whenever needed, either database management software or
additional procedures have to provide these essential capabilities.
 Interference with Shared Data
The concurrent access to shared data via several application programs can lead to some
problems. First, when two concurrent users both want to change the same or related data,
inaccurate results can occur if access to the data is not properly synchronized. Second,
when data are used exclusively for updating, different users can obtain control of different
segments of the database and lock up any use of the data (so called deadlock).
 Organizational Conflict
A shared database requires a consensus on data definitions and ownership as well as
responsibilities for accurate data maintenance. Experience has shown that conflicts on
how to define data, data length and coding, rights to update shared data, and associated
issues are frequent and difficult managerial issues to resolve.
Components of the Database Environment
Data System End
administrators developers users
Application
User interface programs
REPOSITORY DBMS Database
 RepositoryCentralized knowledge base containing all data definitions, screen and report
formats and definitions of other organizations and system components.
1-6 Prof. Erwin M. Globio, MSIT

7. DB212 CHAPTER 1: DATABASE ENVIRONMENT
 Database management system (DBMS)
Commercial software system used to create, maintain and provide controlled access to the
database and repository.
 Database
A shared collection of logically related data, designed to meet the information needs of
multiple users in an organization.
 Application programs
Computer programs that are used to create and maintain the database and provide
information to users.
 User interface
Languages, menu and other facilities by which users interact with various system
components.
 Data administrators
Persons who are responsible for the overall information resources of an organization.
 System developers
Persons such as system analysts and programmer who design new application programs.
 End users
Persons throughout the organization who add, delete and modify data in the database and
who request or receive information from it.
1.5 Review Question
1. Discuss the characteristics of traditional file processing system. Why is the
system criticized?
2. How did the database approach eliminate problems of file processing system?
3. Describe the components of a database system, with the aid of a diagram.
4. Explain why data redundancy is so common in traditional application systems.
5. Where are data definitions maintained in each of the following environment?
a. Traditional file processing system
b. Database system
Prof. Erwin M. Globio, MSIT 1-7