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Database System: Concepts and Design
Conference Paper · December 2003
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Database System : Concepts and Design
1
Database System : Concepts and Design
Mr.Bhojaraju G.*
Dr.M.M.Koganurmath**
Synopsis:
1. Introduction to Database
1.1 Meaning and Definition of Database
1.2 Functions of Database
1.3 Types of Databases
1.3.1 Bibliographic Database
1.3.2 Knowledge Database
1.3.3 Graphic-Oriented Database
1.3.4 Decision-making Database
1.4 Concept of Data Structure
1.4.1 List Structure
1.4.2 Tree / Hierarchical Structure
1.4.3 Network Structure
2. Introduction to DBMS
2.1 Objectives of DBMS
2.2 Functions of DBMS
2.3 Components to DBMS
2.4 Advantages and Disadvantages of DBMS
3. Database Design
3.1 Goals of Database Design
3.2 Logical and Physical View of Database
3.3 View of Data / Architecture of Database System
3.2.1 Data Abstraction
3.2.2 Instances and Schemas
3.2.3 Data independence
3.2.4 Database Languages
3.4 Storage Structures
3.5 Phases in Database Design
4. Application of DBMS to Library and Information System
5. Conclusion
6. References
Database System : Concepts and Design
2
Database System : Concepts and Design
Mr.Bhojaraju G.*
Dr.M.M.Koganurmath**
1. Introduction to Database :
An organization must have accurate and reliable data for effective decision
making. To this end, the organization maintains records on the various facets maintaining
relationships among them. Such related data are called a database. A database system is
an integrated collection of related files, along with details of the interpretation of the data
contained therein. Basically, database system is nothing more than a computer-based
record keeping system i.e. a system whose overall purpose is to record and maintain
information/data.
A database management system (DBMS) is a software system that allows access
to data contained in a database. The objective of the DBMS is to provide a convenient
and effective method of defining, storing and retrieving the information contained in the
database. The DBMS interfaces with the application programs, so that the data contained
in the database can be used by multiple applications and users. In addition, the DBMS
exerts centralized control of the database, prevents fraudulent or unauthorized users from
accessing the data, and ensures the privacy of the data.
Generally a database is an organized collection of related information. The
organized information or database serves as a base from which desired information can
be retrieved or decision made by further recognizing or processing the data. People use
several databases in their day–to-day life. Dictionary, Telephone directory, Library
catalog, etc are example for databases where the entries are arranged according to
alphabetical or classified order.
The term ‘DATA’ can be defined as the value of an attribute of an entity. Any
collection of related data items of entities having the same attributes may be referred to as
a ‘DATABASE’. Mere collection of data does not make it a database; the way it is
organized for effective and efficient use makes it a database.
Database technology has been described as “one of the most rapidly growing areas
of computer and information science”. It is emerged in the late Sixties as a result of
combination of various circumstances. There was a growing demand among users for
more information to be provided by the computer relating to the day-to-day running of
the organization as well as information for planning and control purposes. The
technology that emerged to process data of various kinds is grossly termed as
‘DATABASE MANAGEMENT TECHNOLOGY’ and the resulting software are
known as ‘DATABASE MANAGEMENT SYSTEM’ (DBMS) which they manage a
computer stored database or collection of data.
* Librarian , Fr.C.Rodrigues Institute of Technology, Sector 9A,Vashi, Navi Mumbai – 400 703.
**Librarian, Tata Institute of Social Sciences, Deonar, Mumbai – 400 088.
Database System : Concepts and Design
3
1.1 Meaning and Definition of Database :
An entity may be concrete as person or book, or it may be abstract such as a loan
or a holiday or a concept. Entities are the basic units of objects which can have concrete
existence or constitute ideas or concepts. An entity set is a set of entities of the same type
that share the same properties or attributes .
An entity is represented by set of attributes. An attribute is also referred as data
item, data element , data field, etc. Attributes are descriptive properties possessed by each
member of an entity set. A groping of related entities becomes an entity set.
For ex : In a library environment,
Entity Set -Catalogue –
Entity -of Books, Journals, AV-Materials, etc
Attributes – contains Author, Title, Imprint, Accn. No., ISBN, etc.
The word ‘DATA’ means a fact or more specially a value of attribute of an entity.
An entity in general, may be an object, idea, event, condition or situation. A set of
attributes describes an entity. Information in a form which can be processed by a raw
computer is called data. Data are raw material of information.
The term ‘BASE’ means the support, foundation or key ingredient of anything.
Therefore base supports data.
A ‘DATABASE’ can be conceived as a system whose base, whose key concept, is
simply a particular way of handling data. In other words, a database is nothing more than
a computer-based record keeping. The objective of database is to record and maintain
information. The primary function of the database is the service and support of
information system which satisfies cost.
In short, ” A database is an organized collection of related information stored with
minimum redundancy, in a manner that makes them accessible for multiple application”.
Definition :
1. Prakash Naveen : “Database is a mechanized shared formally defined and central
collection of data used in an organization”.
2. J.M.Martin : ” Database is a collection of inter-related data stored together without
harmful or unnecessary redundancy to serve multiple application”.
3. Mac-Millan dictionary of Information Technology : defines a database as a ” a
collection of inter-related data stored so that it may be accessed by authorized users with
simple user-friendly dialogues”.
1.2 Functions of Database :
The general theme behind a database, is to handle information as an integrated whole.
The general objective is to make information access easy, quick, inexpensive and flexible
for the user.
Controlled redundancy : Redundant data occupies space and therefore is wasteful.
By controlled redundancy, system performance is improved.
User-friendly (i.e. ease to learning and use) : A major feature of a user-friendly
database package is how easy it is to learn and use.
Database System : Concepts and Design
Data independence : means it allows for changes at one level of the database without
affecting the other levels i.e. changing hardware and storage procedures or adding
new data without having to rewrite application program.
Economy (i.e. more information at low cost) : Using, storing and modifying data at
low cost are important.
Accuracy and integrity : Even if redundancy is eliminated, however, the database
may still contain incorrect data. Centralized control of the database helps in avoiding
these situation. The accuracy of a database ensures that data quality and content
remain constant. Integrity controls detect data inaccuracies where they occur.
Recovery from failure : With multi-user access to a database, the system must
recover quickly after it is down with no loss of transactions. It helps to maintain data
accuracy and integrity.
Privacy and Security : For data to remain private, security measures must be taken
to prevent unauthorized access i.e. complete jurisdiction over the operational data.
DBMS ensures proper security through centralized control.
Performance : It emphasizes response time to inquiries suitable to the use of the data
depends on the nature the user-database dialogue.
Database retrieval, analysis, storage :.It facilitates Database retrieval, analysis and
storage.
Compatibility : Usefulness i.e. hardware/software can work with different
