Database Concepts Pdf Free Download

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, the 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. Citation: G Bhojaraju, MM Koganurmath (2003) Database Management : Concepts and Design In: Proceedings of Knowledge management in special libraries in digital environment : XXIV All India Conference of IASLIC, 15-18 December, 2003, Survey of India, Dehra Dun Edited by:Amitabha Chatterjee ... et al.. 385-398 Kolkata : Indian Association of Special Libraries & Information Centres, 2003.: Series: Special publication / IASLIC, 0972-3668 ; no. 43 Available from: https://www.researchgate.net/publication/257298522_Database_Management_Concepts_and_Design

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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

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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 e ntities 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

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 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

computers.

 Concurrency control : is a feature that allows simultaneous access to a database,

while preserving data integrity.

 Support : Support of complex file structure and access path. Ex : MARC

 Data Sharing : A database allows sharing of data under its control by any number of

users.

 Standards can be enforced : Standardizing stored data formats is particularly

desirable as an aid to data interchange between systems.

1.3 Types of Databases :

Database is considered as a central pool of data which can be shared by a

community of users. There are three yard sticks to determine the nature of data we can

deal with. They are :

a. Whether data is free of format or whether it is formatted.

b. Whether definition of data is of the same size as data itself.

c. Whether the data is active or passive.

Whether these yard sticks are applied to data. We can classify database into four kinds

which are

1.3.1 Bibliographic Databases

1.3.2 Knowledge Databases

1.3.3 Graphic-Oriented Databases

1.3.4 Decision-making Databases

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1.3.1 Bibliographic Databases : have data which is free of format (unformatted data).

They are composed of textual data which, by it's very nature, displays little or no format.

Such databases are often used in Library and information system. Here data could be

composed of abstracts of books and such documents with key words and key phrases.

Through the abstract, one can determine the document is of interest or not. Bibliographic

database contains descriptive information about documents, titles, authors, Journal name,

Volume and Number, date, keywords, abstract, etc.

1.3.2 Knowledge Databases : are used in Artificial Intelligence applications. The data

contained in these is discrete and formatted. In these there are typically man y kinds of

data, with only a very few occurrence of each kind. Such databases having the size of the

data is as large as the definition of the data.

1.3.3 Graphic-Oriented Databases : could possibly used in Computer-Aided Design

(CAD). The data in such database is characterized as being active. This means that data is

a procedure capable of being executed. Any modification can be made in data, as the

above 1 and 2 cannot be executed in a computer.

Ex : Computer-Aided Design (CAD)

Computer-Aided Learning (CAL)

Computer-Aided Instruction (CAI)

1.3.4 Decision-making Databases : are used in corporate management and allied

administrative tasks. Using data contained in these databases, one could handle problem

like resource planning and sales forecasting. These databases are characterized by the fact

and their data contents are :

a. Formatted

b. Far longer than description

c. Passive

These Decision-making databases are often referred to as just databases.

Depending upon the kind of databases being handled Database Management Systems

(DBMS) can be classified as for example : Bibliographic Database Management Systems,

Knowledge Database Management Systems and so on.

1.4 Concept of Data Structure :

Data are structured according to the Data model. A group of data elements handled

as a unit. Ex : Book details - is a data structure consisting of the data elements - Author

name, Title, Publisher's name, ISBN and Quantity.

There are several different approaches to analyzing the logical structure of data in

complex databases. Although all DBMS's have a common approach to data management,

they differ in the way : the structure of data.

There are three types of data structure, viz

1.4.1 List Structure

1.4.2 Tree / Hierarchical Structure

1.4.3 Network Structure

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1.4.1 List Structure : A list is nothing morethan a special data structure made up of data

record where the Nth record is related (N-1) and (N-2) simply because of positioning.

This brings one-to -one relationship. This structure is illustrated as below :

Fig. Simple List Structure

1.4.2 Tree / Hierarchical Structure : A tree structure is a non-linear multilevel

hierarchical structure in which each node may be related to N-nodes at any level below it.

But to only one node above it in the hierarchy.

The entry is from the top and the direction of search or passing is downward and

no branches on the tree trunk (touch).

Data storage in the form of a parent-child relationship. The origin of a data tree is

the root . Data located at different levels along a particular branch from the root is called

the node . The last node in the series is called the leaf . Each child has pointers to

numerous siblings and there is just one pointer to the parent thus resulting in a one-to-

many relationship.

Fig. Tree / Hierarchical Structure

1.4.3 Network Structure : Network Structure is another form of hierarchical structure.

In this view as in the hierarchy approach, the data is represented by records and links.

However, a network is a more general structure than a hierar chy.

A network structure allows relationships among entities. Here user views the

database as a number of individual record occurrences in which a given node may have

any number of subordinates nodes. Network Structure is equated to a graph structure.

This brings many-to -many relationship. The relationship between the different item is

called as sets .

Database System : Concepts and Design

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Fig. Network Structure

2. Introduction to Database Management System (DBMS) :

A DBMS is essentially a collection of interrelated data and a set of programs to

access this data. This collection of data is called the Database which facilitates storage,

retrieval and management of information.

A DBMS consists of a collection of interrelated data and a set of programs to

access those data. The collection of data, usually referred to as the database. The primary

goal of DBMS is to provide an environment that is both convenient and efficient to use in

retrieving and storing database information.

Database systems are designed to manage large bodies of information. The

management of data involves both the definition of structures for the storage of

information and the provision of mechanisms for the manipulation of information.

In addition, the database system must provide for the safety of the information

stored, despite system crashes or attempts at unauthorized access. If data are to be shared

among several users, the system must avoid possible anomalous results.

DBMS is a software system which manages the databases providing facilities for

organization access and control. DBMS is like an operator for database. Database is

passive where as DBMS is active one. It provides the interface between the data file on

disk and the program that requests processing.

2.1 Objectives of DBMS :

The primary objective of a DBMS is to provide a convenient environment to

retrieve and store database information. It support single-user and multi-user

environment.

 Provide for mass storage of relevant data.

 Make access to the data easy for user.

 Provide prompt response to user requests for data.

 Make the latest modifications to the database available immediately.

 Eliminate the redundant data.

 Allow multiple users to be active at one time.

 Allow for growth in the database system.

 Protect the data from physical harm and unauthorized access.

 Control over data correctness, consistency, integrity, security, etc.

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2.2 Functions of DBMS :

According to the Codd, a comprehensive DBMS provides eight major functions. viz

 Data storage, retrieval and update : A database may be shared by many users thus,

the DBMS must provide multiple users views and allow users to store, retrieve and

update easily and effectively.

 Data dictionary and directory : The DBMS must maintain a user accessible data

dictionary.

 Transaction integrity : A transaction is sequence of steps that constitute some well

defined business activity. To maintain transaction integrity, the DBMS must provide

facilities for the user or application program to define transaction boundaries i.e. the

logical beginning and end of transactions. The DBMS should then commit changes

for successful transactions and reject changes for aborted transactions.

 Recovery Services : The DBMS must be able to restore the database in the events of

some system failure. Sources of system failure include operator error, disk head

crashes and program errors.

 Concurrency Control : Since a database is a shared by multiple users, two or more

users may attempt to access the same data simultaneously. If two users attempt to

update the same data record concurrently, erroneous results may occur. Since the

safeguards must be built into the DBMS to prevent or overcome the efforts of

interference.

 Security mechanisms : Data must be protected against accidental or intentional

misuse or distraction. The DBMS provides mechanisms for controlling access to data

and for defining what action may be taken by each user.

 Data Communication interface : Users often access a database by means of remote

terminates in telecommunication network. A telecommunication monitor is used

process the flow of transactions to and from the remote terminates. The DBMS must

provide a interface with one or more telecommunication monitors so that all the

necessary functions are performed and the system will assist, rather than a burden on

the end user.

 Integrity services: The DBMS must provide facilities that assist users in

manufacturing the integrity of their data. A variety of edit checks and integrity

constraints can be designed into the DBMS and its software interfaces. These checks

are normally administered through the data dictionary.

2.3 Components of a DBMS :

A DBMS is a complex structure that is used to manage, store and manipulate data

and the metadata used to describe the data. It is utilized by a large variety of users to

retrieve and manipulate data under its control. A system is a composed of set of

interrelated components.

1. Atleast one person who owns and is responsible for the database.

2. A set of rules and relationship that defines and governs the interactions among

elements of the database.

Database System : Concepts and Design

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3. People who put data into the database.

4. People who get data out of the database.

5. The database itself.

3. Database Design :

Database design is the design of the database structure that will be used to store

and manage data rather than the design of the DBMS software. Once the database design

is completed, the DBMS handles all the complicated activities required to translate the

designer's view of the structures into structures that are usable to the computer.

A poorly designed database tends to generate errors that are likely to lead to bad

decisions. A bad database design eventually can be self correcting: organizations using

poorly designed databases often fail because their managers do not have access to timely

(or even correct) information, thereby dominating the bad database design.

The availability of a DBMS makes it possible to tackle far more sophisticated

uses of the data resources, if the database is designed to make use of that available power.

The kinds of data structures created within the database and the extent of the relationships

among them play a powerful role in determining how effective the DBMS is. Therefore,

database design become a crucial activity in the database environment.

Database design is made much simpler when we use models. A Database model is

a collection of a logical constructs used to represent the data structure and the data

relationships found within the database i.e. simplified abstractions of real-world events or

conditions. If the models are not logically sound, the database designs derived from them

will not deliver the database system's promise to effective information drawn from an

efficient database. "Good models yield good database design that are the basis for good

applications".

3.1 Goals of Database Design :

Database Design normally involves defining the logical attributes of the database

designing the layout of the database file structure.

The main objectives of database design is

1. To satisfy the information content requirement of the speci fied user and application.

2. To provide a natural and easy way to understand structuring of the information.

3. To support processing requirements and any performance objectives such as

i. Response time

ii. Processing time

iii. Storage space

The main objective of the database design is to ensure that the database meets the

reporting and information requirements of the users efficiently. The database should be

designed in such a way that :

i. It eliminates or minimizes data redundancy.

ii. Maintains the integrity and independence of the data.

Database System : Concepts and Design

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3.2 Logical and Physical View of Database :

Computer Application DBMS Operating Database

Program System

(IOCS)*

User logical Program logical Overall logical Physical View

View View View

(Schema)

1 2 3 4

* IOCS- Input/ Output Control System

In database design, several views of data must be considered along with the

persons who use them. There are three views :

1. The overall logical view

2. The program logical view

3. Physical view

The logical view is what the data look like, regardless of how they are stored

whereas the

physical view is the way data exist in physical storage, it deals with how data are stored,

accessed or related to other data in storage.

Four views of data : THREE logical views and ONE physical view.

The logical view as the user's view, the programmer's view and the overall logical

view (schema).

The overall logical view (schema) helps the DBMS to decide what data in storage

it should act upon as required by the application program.

A DBMS is a collection of interrelated files and a set of programs that allow users

to access and modify these files. A major purpose of a database system is to provide users

with an abstract view of the data i.e. the system hides certain details of how the data are

stored and maintained.

3.3 An Architecture for a Database System :

3.3.1 Data Abstraction : Many database system users are not computer trained,

developers hide the complexity from users through several level of abstraction, to

simplify users' interaction with the system. The architecture is divided into three general

levels : internal, conceptual and external.

Database System : Concepts and Design

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a. Internal / Physical level : The internal level is the one closest to physical storage i.e.

one concerned with the way in which the data is actually stored. It is the lowest level of

abstraction describes how the data are actually stored. At the physical level, complex low

level data structures are described in detail.

b. Conceptual / Logical level : is a "level of indirection" between the internal and

external. The next higher level of abstraction describes what data are stored in the

database, and what relationships exists among those data. The entire database is thus

described in term of a small number of relatively simple structures. This level is used by

Database Administrators(DBA), who must decide what information is to be kept in the

database.

c. External / View level : The external level is the one closest to the users, i.e. the one

concerned with the way in which the data is viewed by individual users. It is the highest

level of abstraction describes only part of the entire database. Despite the use of simpler

structures at the logical level, some complexity remains, because of the large size of the

database. Many users of the database system will not be concerned with all this

information. Instead, such users need to access only a part of the database so that their

interaction with the system is simplified, the view level of abstraction is defined. The

system may provide many views for the same database.

If the external level is concerned with the individual user views, the conceptual

level may be thought of as defining a community user view. In other words, there will be

many "external views," each consisting of a more or less abstract representation of some

portion of the database, and there will be a single "conceptual view," consisting of a

similarity abstract representation of the database in its entirety. Likewise, there will be a

single "internal view," representing the total database as actually stored.

Fig. The three levels of architecture of a DBMS

3.3.2 Instances and schemes : Databases change over time as information is inserted or

deleted. The collection of information stored in the database at a particular moment is

called an instance of the database. The overall design of the database is called the

database schema. Schemas are changed infrequently, if at all.

Database System : Concepts and Design

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The view at each of these levels is described by a Schema. A schema is an outline

or a plan that describes the records and relationships existing in the view. The word

schema is used in the database literature for the plural instead of schemata, the

grammatically correct word. The schema also describes the way in which entities at one

level of abstraction can be mapped to the next level.

Database systems have several schemas, partitioned according to the levels of

abstraction(that we discussed). At the lowest level is the physical schema; at the

intermediate level is the logical schema; and at the highest level is a subschema. In

general, database system support one physical schema, one logical schema and several

subschemas.

3.3.3 Data independence : The ability to modify a schema definition in one level

without affecting a schema definition in the next higher level is called data

independence. There are two levels of data independence viz.

a. Physical data independence : is the ability to modify the physical schema without

causing application programs to be rewritten. Modifications at the physical level are

occasionally necessary to improve performance.

b. Logical data independence : is the ability to modify the logical schema without

causing application programs to be rewritten. Modifications at the logical level are

occasionally necessary whenever the logical structure of the database is altered.

Logical data independence is more difficult to achieve than is physical data

independence, since the application programs are heavily dependent on the logical

structure of the data that they access.

3.3.4 Database languages : Data Sublanguage (DSL) is a subset of the total language i.e.

concerned with the database objects and operations. DSL is a user's / query language

which is being embedded in a host language. In principle, any given DSL is really

combination of two languages :

a. Data Definition Language (DDL) : is one which specify the database schema. A

database schema is specified by a set of definitions. This definition includes all the

entities and their associated attributes as well as the relationships among the entities. The

result of compilation of DDL statements is a set of tables i.e. stored in a special file called

data dictionary or data directory, which caontains metadata i.e. data about data. This

file is consulted before actual data are read or modified in the database system.

The storage structure and access methods used by the database system are

specified by a set of definitions in a special type of DDL called a data storage and

definition language.

b. Data Manipulation Language (DML) : is one which is used to express data queries

and updates i.e. manipulate data in the database. DML helps in

- the retrieval of information stored in the database

- the insertion of new information into the database

- the deletion of information from the database

- the modification of information stored in the existing database

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A DML is a language that enables users to access or manipulate data as organized

by the appropriate data model. There are basically two types :

i. Procedural DMLs : requires a user to specify what data are needed and how to get those

data.

ii.Non- Procedural DMLs : requires a user to specify what data are needed without

specifying how to get those data.

Mapping : There are two levels of mapping :

i. one between the external and conceptual levels of the system; and

ii. the other between the conceptual and internal levels.

The Conceptual/Internal mapping defines the correspondence between the

conceptual view and the stored database. The External/Conceptual mapping defines the

correspondence between a particular external view and the conceptual view.

Fig. Database System Architecture

The DBMS is the software that handles all access to the database. Conceptually

what happens is the following :

1. A user issues an access request, using some particular Data Manipulation

Language(DML);

2. the DBMS intercepts the requests and interprets it;

Database System : Concepts and Design

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3. the DBMS inspects, in turn the external schema, the external/conceptual mapping, the

conceptual schema, the conceptual/internal mapping, and the storage structure definition;

and

4. the DBMS performs the necessary operations on the stored database.

3.4 Storage Structures :

Storage Structures describes the way in which data may be organized in secondary

storage i.e. direct access media such as disk packs, drums and so on.

Fig : The Stored record interface

User operations are expressed (via the DML) in terms of external records, and

must be converted by the DBMS into corresponding operations on internal or stored

records. These later operations must be converted in turn to operations at the actual

hardware level, i.e. to operations on physical record or blocks. The component

responsible for this internal/physical conversion is called an access method. Its function

is to conceal all device-dependent details from the DBMS and to present the DBMS with

a stored record interface. The stored interface thus corresponds to the internal level, just

as the user interface corresponds to the external level. The Physical record interface

corresponds to the actual hardware level.

The stored record interface permits the DBMS to view the storage structure as a

collection of stored files, each one consisting of all occurrences of one type of stored

record(see architecture of DBMS).Specifically, the DBMS knows (a). what stored files

exist, and, for each one, (b) the structure of the corresponding stored record, (c) the stored

field(s), if any, on which it is sequenced, and (d) the stored field(s), if any, that can be

used as search arguments for direct access. This information will all be specified as part

of the storage structure definition.

Database System : Concepts and Design

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3.5 Phases in Database Design :

3.5.1 First phase : The overall purpose of the database initial study is to

a. analyze the organization/system situation

b. define problem and constraints

c. define objectives

d. define scope and boundaries.

3.5.2 Second phase : The second phase focuses on the design of the database model that

will support organization operations and objectives.

In this phase, we can identify six main phases of the database design :

I. Requirements collection and analysis

II. Conceptual database design

III. Choice of DBMS

IV. Data model mapping

V. Physical database design

VI. Database system implement

Fig : Procedure flow in database design

Database System : Concepts and Design

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I. Conceptual Design : It involves two parallel activities

a. Conceptual scheme design

b. Transaction design

a. The first activity of Conceptual design examines the data requirements resulting

from Phase 1 and produces a Conceptual database scheme.

b. The second activity Transaction design examines the database applications

analyzed in Phase 1 and produces high-level specifications for the presentation. The goal

of Phase 2 is to produce a Conceptual schema for the database i.e. independent of a

specific DBMS.

In this stage, data modeling is used to create an abstract database structure that

represents real world objects in the most realistic way possible. The conceptual model

must embody a clear understanding of the transaction or system and its functioning areas.

This design is software and hardware independent.

i. Data Analysis and Requirements : Before we can effectively design a database, we

must know the expectations of the users and the intended users of the database as much

detail as possible. The process of identifying and analyzing the intended users is called "

Requirements collection and analysis".

It is the first step in Conceptual design is to discover the data element

characteristics. Appropriate data element characteristics are those that can be performed

into appropriate information. Therefore designers has to focussed on :

a. information needs;

b. information users ;

c. information sources; and

d. information constitution.

In order to develop an accurate data model, the designer must have a thorough and

complete understanding of the organization's data. Consequently, the designer must

identify the organization's goals and objectives, rules and analyze their impact on the

nature, role and scope of data.

ii. Entity-Relationship modeling and normalization : Before creating the E-R model(

data model) the designer must communicate and enforce appropriate standards to be used

in the documentation of the design. Failure to standardize documentation often means a

failure to communicate later. And communication failures often leads to poor design

work.

iii. Data model verification : The E-R model must be verified against that the proposed

system processes in order to corroborate that the intended processes can be supported by

the database model.

Verification requires that the model can be run through a series of test against :

a. End user data views and their required transactions : SELECT, INSERT, UPDATE and

DELETE operations and queries and reports.

b. Access paths, security and concurrency control.

c. System / Business-imposed data requirements and constraints.

Database System : Concepts and Design

17

iv. Distributed Database Design : A distributed database stores logically related data

into two or more physically independent sites connected via a computer network. Design

portions of a database may reside in different locations. Processes that access the

database may also vary from one location to another.

II. DBMS Software selection : The selection of DBMS software is critical to the

information systems' smooth operation. Consequently, the proposed DBMS software's

advantages and disadvantages should be carefully studied. The end user must be made

aware of the limitations of both the DBMS and the database in order to avoid false

expectations.

Factors affecting the purchasing decision of DBMS are :

(i).Cost, (ii). DBMS features a nd tools, (iii). Underlying data model, (iv). Portability, and

(v). DBMS hardware requirements.

III. Logical Design : Logical design is used to translate the Conceptual design into the

internal model for a selected DBMS (such as DB2, SQL Server, Oracle, IMS, Informix,

Access, Ingress and so on). Logical Design follows the decision to use a specific database

model (hierarchical, network or relational ). Once the database model is identified, we

can map the Conceptual design onto a Logical design that is tailored to the selected

database model. At this stage, the logical design is Software dependent. This includes

mapping all objects in the model to the specific constructs used by the selected database

software. The right to use the database is also specified during the logical design phase.

In short, the logical design translates the software independent conceptual model

into a software dependent model by defining the appropriate domain definitions, the

required tables and the necessary access restrictions.

IV. Physical Design : The stage is now set to define the physical requirements that allow

the system to function within the selected hardware environment.

Physical design is the process of selecting the data storage and data access

characteristics of the database. The storage characteristics are a function of the types of

devices supported by the hardware, the type of the data access methods supported by the

system and the DBMS. Physical design affects not only the location of the data in the

storage device(s) but also the performance of the system.

V. Database system implement : After the database has been created, the data must be

loaded into the database tables. If the data are currently stored in a format different from

the required by the new DBMS, the data must be converted prior to being loaded.

During the implementation and loading phase, we also must address performance,

security, backup and recovery, integrity, company standards and concurrency control.

4. Application of DBMS to Library and Information System :

There are two software packages related to Library and Information System. viz.

4.1 DBase III Plus : is one of the most popular DBMS on personal computers. It is the

third major version of the classic dBase database management system series from

Ashton Tate. It is powerful and flexible system for storing, organizing, analyzing and

Database System : Concepts and Design

18

retrieving information on a microcomputer. It can be interacted by two modes: one is the

assistant/menu mode and other is the command mode.

4.2 CDS/ISIS : is menu driven generalized information storage and retrieval system

designed specially for the computerized management of structured non-numerical

databases. It contains 8 programs written in PASCAL language. In India, it is distributed

by the National Information System for Science and Technology (NISSAT), Department

of Scientific and Industrial Research, New Delhi on behalf of UNESCO.

5. Conclusion :

The field of information technology is growing out in a very fats rate in India.

Recently, new types requirements in database processing capabilities have been

increasing in several area of application. At the same time, a variety of sophisticated

techniques have been developed and powerful modeling capabilities.

Database development process includes information gathering, selection of quality

information, computation and consolidation or abstracting in case of bibliographic

database, coding, structuring the compiled data into database format, data entry and

editing, updating, quality control at all levels and maintenance.

As such database expresses a concept which has evolved and change gradually over

the years since the term was coined. Implementation of the concept has made possible by

improving hardware and software technology as made available increasingly regarded as

a vital corporate resource.

India is a large country with vast natural resources. Still the information is scarce. It is

not that information is not generated but gets locked on papers to be put in files in the

custody of various government organizations and research institutions. India needs

database in view of liberalization of Indian economy and the globalization of business.

The increasing international interaction requires formation of relevant and viable

database.

In addition to the database with in an organization a vast new demand is growing

for database services. It has developed tremendously over the time to support the

changing world's need control and communication philosophies within the organizations

as well as outside as seen by the users of this service.

6. References :

1. Rob,Peter and Coronel Carlis : Database Systems: Design, implementation and

management -

4th ed. Cambridge, Course Technology, 2000 (p 1-55,286-321)

2. Date, C J : An Introduction to Database Systems - 3rd ed. Vol. 1

New Delhi: Narosa,1996 (p 3-32,33-61,63-80)

3. Silberschatz,Abraham and others: Database System Concepts - 3rd ed.

New Delhi: McGraw Hill, 1996(p 1-21)

4. Desai,Bipin C : An Introduction to Database Systems

New Delhi: Galgotia, 1996 (p 2-33)

Database System : Concepts and Design

19

5. Taxali, R N : PC-Software: Made simple

New Delhi: Tata MacGraw Hill, 1996 (p 337)

6. Awad,Elias M : Systems Analysis and Design

New Delhi: Galgotia,1989 (p 25,31,78,323,332-337)

7. Llewellyn,Robert W : Information Systems

New Jersey: Prentice-Hall Inc, 1976 (p 251,829-835)

8. Balaguruswamy, E and others : Dbase III Plus: A guide and workbook

Madras: MacMillan, 1989 (p 3,23)

9. Choudhury,G G : Text retrieval systems in information management

New Delhi: New Age International Ltd, 1996 (p 14-15,23-32)

10.Kumar,P S G : Computerization of Indian Libraries

Delhi: B.R.Publishing Corporation, 1987 (p 80)

11.Prakash, Naveen : Introduction to Database Management

New Delhi: Tata MacGraw Hill, 1991 (p 15-16)

12. Simpson,Alan : Understanding dBase III Plus

New Delhi: BPB Publications, 1993 (p xx )

ResearchGate has not been able to resolve any citations for this publication.

Database Systems: Design, implementation and management - 4 th ed. Cambridge, Course Technology

• Peter Rob
• Coronel Carlis

Rob,Peter and Coronel Carlis : Database Systems: Design, implementation and management - 4 th ed. Cambridge, Course Technology, 2000 (p 1-55,286-321)

Abraham and others: Database System Concepts -3 rd ed

• Silberschatz

Silberschatz,Abraham and others: Database System Concepts -3 rd ed. New Delhi: McGraw Hill, 1996(p 1-21)

PC-Software: Made simple New Delhi: Tata MacGraw Hill

• R N Taxali

Taxali, R N : PC-Software: Made simple New Delhi: Tata MacGraw Hill, 1996 (p 337)

Systems Analysis and Design New Delhi: Galgotia

• Elias M Awad

Awad,Elias M : Systems Analysis and Design New Delhi: Galgotia,1989 (p 25,31,78,323,332-337)

Information Systems New Jersey

• Robert W Llewellyn

Llewellyn,Robert W : Information Systems New Jersey: Prentice-Hall Inc, 1976 (p 251,829-835)

Dbase III Plus: A guide and workbook Madras

• E Balaguruswamy

Balaguruswamy, E and others : Dbase III Plus: A guide and workbook Madras: MacMillan, 1989 (p 3,23)

Text retrieval systems in information management New Delhi: New Age International Ltd

• G G Choudhury

Choudhury,G G : Text retrieval systems in information management New Delhi: New Age International Ltd, 1996 (p 14-15,23-32)

Computerization of Indian Libraries Delhi

• P Kumar

Kumar,P S G : Computerization of Indian Libraries Delhi: B.R.Publishing Corporation, 1987 (p 80)

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