This document provides an introduction to database management systems. It discusses what data and information are, and how data is processed into meaningful information through models. Databases organize related data and provide controlled data redundancy. Historically, clay tablets, quipus, and punched cards were used to store and process data. A database manages data through its key elements - data, relationships between data, constraints on the data, and a schema that defines the organization. The database serves the information needs of an entire enterprise by centrally storing and sharing information across departments.

1. INTRODUCTION TO DATABASE
MANAGEMENT SYSTEM
STAFF-INCHARGE :
Mrs.S.SUBHASHINI MCA.,M.PHIL.,(SET)

2. INTRODUCTON :
• Data is a collection of facts such as numbers,
words, measurements, observations or just
descriptions of things.
* Information is processed data that put into
a meaningful and useful context to make best
decisions.
• It consists of data,images,text,documents,
voice,video etc.,
• It is a backbone of any organisation.
• It is a critical factor to gain competetive edge in
any organisation.
• It is most critical resource of an organisation.

3. Information cycle
• Input data are processed through models to
create information .
• Recipients receives information, makes
decision and then takes an action.
• Action triggers other action or events to
provide results.
• Resultant data are captured and can be used
as input data for other cycles

5. HISTORY OF INFORMATION
• In 4500 B.C ,clay tablets are used to record data.
• Clay tablets were used to store information
about receipts,disbursements, loans, purchases ,
sales, leases, partnership formation, contracts
etc.
• 500 yearsago, Inca indians of south america
used accounting apparatus called quipus.
• It consists of thousands of knotted strings and
• Knots were made in cords to represent units,
tens,hundreds etc.

6. HISTORY OF INFORMATION
Cords were differently colored to represent
lands,economic productivity , matters relatingto war
etc.
* Quipus were created & Maintained by high
officials like judges,commanders,family heads,
village head etc.,
*Art of data processing was already existed from
early ages.

7. HISTORY OF INFORMATION
Quipuamayus : People who built these
information system with knots was called “
Quipuamayus “
• All successful civilization had some kind of data
storage & retrieval system remains .
• Lot of information needed for internal decisions
& for successfully running organisation.

8. Quality of Information
• Quality information is accurate , timely and
relevant information.
* 3 Key attributes of information are
1. Accuracy
2. Timeliness
3. Relevancy
1.Accuracy :
- It means that information is clear and
accurate that reflects meaning of data.
- It also means information with no mistakes
and Error , free from bias.

9. 2.Timeliness :
• It means getting timely information with in
the needed time to the recipients.
. Recipients get timely information when they
want to use it at the very useful time.
3.Relevancy :
• It means use of a piece of information for a
particular person .
* Information relevant for one person might not
be relevant for another.
* Relevancy is a very subjective matter .

10. Information Processing
Definition :
Information Processing is the acquisition ,
storage, organisation, retrieval , display and
Dissemination of information .
* Few decades back , data processing was done
manually .
• Manual processing was good when amount of
data to be processed is less.
• punched cards ,magnetic tapes were used
( Initial Stage )

11. * Using punched cards, magnetic tapes only
batch processing of information was done .
• In this batch processing approach , individual
transaction is not managed .
• No possibility of giving answers quickly for
transactions in batch processing approach.
• Answers did not reflect current state of affairs
( might be a week (or) more out of date .

12. *In batch processing approach, relevancy of data
is maintained . But timeliness and accuracy of
information cannot be achieved .
*To overcome disadvantages of batch processing,
database approach can be used .
• Database approach is used to organise data in
an effective way than batch processing
approach .
• Database approach makes searching,
processing, retrieving of data very easy , quick
and effective.

13. Information and the enterprise
Enterprise : An Enterprise is the group of people
with a common goal and they uses certain
resources to achieve this goal .
*An enterprise acts as a single entity .
* In Traditional approach , an organisation is
divided in to different departments .
*Each department creates its own information
and generates its own.

14. *

15. • Information available only to top
management , but not to other departments.
• In Current Approach, Entire organisation is
considered as a system and all the
departments are its subsystems.
• Information of all subsystems stored
centrally .
• Made available to all departments
( subsystems ).
• Current approach helps organisation- move
forward as a single entity
effectively with central database.

17. Database
Definition: Database is a collection of data
designed to be used by different people .
• It has a collection of interrelated data stored together.
• It provides controlled redundancy of data .
• It can serve one or more applications.
• Data stored in database are independent of the
user programs .
• Organised way -A computer program quickly select
desired pieces of data.
• Traditional databases are organised by fields,
records and files.

18. Components (or) Elements of
Database
• A database consists of four elements .
1.Data
2.Relationship
3.Constraints
4.Schema
1.Data:
* Data is a collection of facts such as numbers,
words, measurements, observations or just
descriptions of things.

19. • Data exist in various form such as numbers ,text , bits,
bytes, images etc.
• Stored in binary form in computer memory.
• Stored as bytes in electronic memory.
• Stored as facts in person’s mind .
• In DBMS,Data files are the files that store the
database information.

20. * Indexfile , data dictionaries store administrative
information known as metadata.
Metadata : Meta data is an administrative information
Stored in index file , data dictionaries etc.
* It is data about data .
2.Relationship:
* It represent a correspondance between the
various data elements.
3.Constraints :
* constraints are predicate that define correct database
states.

21. 4. Schema : Describes organisation of data &
relationships with in the database .
*Defines various views of databases .
• Separates physical aspects of data storage from logical
aspects of data representation.
• Three schema are
a) Internal schema :
Defines how & where data are organised in physical
data storage .

22. b)Conceptual schema :
Defines stored data structure in terms of database
model used.
c)External schema :
Defines a view ( or) views of the database for
particular user.