The document provides an introduction to database management systems (DBMS). It discusses what a DBMS is, common applications of databases, the difference between data and information, database components, objectives of a DBMS, the evolution of DBMS components over time including data manager, disk manager, data dictionary, query processor, and more. It also covers different database models such as hierarchical, relational, network, object-oriented, and classifications of DBMS based on data model, number of users, and database distribution.

1. DBMS
Unit -1

2. INTRODUCTION
 collection of inter related data & set of programms to
access that data.
 Dbms contain information about a particular enterprise.
 Dbms provides an environment that is both convenient &
efficient to use.
 Databaseapplications:banking,airlines,universities,sales,ma
nufacturing.

3.  Data & information : data is a raw collection of fact
about people , place objects . Data is given by user
to the computer , it requieres processing.
 Information is processed data that increase the
knowledge of the person . It is meaningful data in an
organized form . It is given by the computer to the
user. it is processed data & it’s meaningful.
 Database is a collection of related data . A data has
several database elements like table, quries & etc.
data is process to produce information.

4. Objectives of dbms
• provide storage of relevant data.
• Making easy access to data for authorized
users.
• Providing prompt response to users request for
data.
• Eliminate redundantly (duplicate )data.
• Allow multiple users to be active at one time.
• Allow the growth of database system.
• Provide data integrity.

5. Evolution of Dbms : 9 components
1. Data manager
2. Disk manager
3. Data dictionary
4. Query processor
5. File manager
6. Data definitions language compiler
7. Telecommunication system
8. Data files
9. Access aids

6. 1. Data manager : it is the central s/w component of
dbms. It is the referred to as data base control
system operationsin the user’s quries coming
directly. It maintain the consistency & integrity of
data as well as its security are also performed by
data manager. It is also entrusted with backup &
recovery oprations.
2. Disk manager : it is part of os of the host computer
& physical i/p &o/p operations are performed by it .
The disk manager tranfers the block or page
requested by the file manager.

7. 3. Data dictionary : the structure & usage of data
contained in data base , the meta data is maintained
in a data dictionary. The data dictionary which is data
base itself , documents the data base . It is used to
learn what each piece of data & the various
synonyms of data field mean.
4. Query processor : the query processor uses the
data dictionary to find structure of the relevance
portion of data base & uses its information in
modifying the query and preparing an optimal plan to
access the data base.

8. 5. File manager : responsibility for the structure of the
files & managing the file space rests with the file manager.
It is also responsible for locating the block containing the
required record , requesting this block from the disk
manager & transmitting the required record to the data
manager.
6. Data definition language compiler : the DDL computer
converts the data definition st mts in to a set of tables .
The tables contains the meta – data concerning the
database & are in a form that can be used by other
components of the DBMS.

9. 7 . Telecommunication system : it is not part of DBMS but
the DBMS works closely with the systems the subject is
covered extensively . The online user may communicate
with data base directly or indirectly via a user interface &
an application program. Message from the user are routed
by the telecommunication system & responses are sent
back back to user.
8. Data files : data files contain the data portion of the
data base.
9. Access aids : to improve the performance of a DBMS , a
set of access aids in the form of indexes are usually
provided in a data base systems . Commands are provided
to build & destroy additional tempory indexes .

10. Classification of database modes
• Hierarchical database model
• Relational models
• Network models
• Object oriented database model
• Entity relationship model
• The object relational models

11. • Relational models : The most common model , the
relational model sort’s data in to table also known
as relations each of which consists of rows &
columns. Each column lists an attribute of the
entity in question , such as price , zip code or birth
date. The model also accounts for the type of
relationships b/w those tables , including one –to-
one ,one- to- many & many-to-many relationship .
Relational data base are typically written in SQL.
The model was introduce by E.F.codd in 1970.

12. Student id First name Last name
1896456 Leela Sri
1876786 mani Kumar
College id College name
676554 Loyola college
554454 Kbn college
Student id College id Type of group Examination
data
1896456 Leela sri 04/05/2020

13. • Hierarchical mode : the hierarchical model organizes data
into tree like structure ,where each recorded as a single
parent or rood. Sibling records are sorted in a particular order
it is sorting order .
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14. • Network model : The network model builds on the hierarchical model
allowing many-to-many relationships b/w linked records, implying
multiple parent records. Based on mathematical set theory . The model is
constructed with sets related records . Each sets consists of one owner or
parent record & one or more members or child record. It is popular in 70’s
it was formally defined by the (CODASY2) conference on data system
language.
VENDOR
EMP CUSTOMER PRODUCT
SALES
TRANSACTION

15. • Object oriented database model : This model
defines a database as a collection of objects or
reusable b/w elements withs associated
features & method . There are several kinds of
object oriented database.
• Multimedia database : incorporates media ,
such as images ,that could not be stored in
relational database.

16. • Hypertext database : it allows any object to link to any other
object . Its useful for organizing lost of disparate data .
object 1 : sales report object 1 instance
Month
Product code
Vendor
revenue
01-15-15
54
154-234
$ 819Customer
Product code
Product name
Sales assaiate
Date of sale
price
Object 2 :sales activity

17. • Object relational model : this hybrid database
models combines the simplicity of the
relational model with some of the advanced
functionality of the object – oriented database
model. In essence it allows designers to
incorporate objects into the fanliar table
structure ODBC,JDBC are extensions of the
languages & interfaces used by relational
models.

18. Classification of dbms : DBMS can be classified
based on several criteria , such as data model , user
numbers & database distribution.
Classification based on data model : most popular data
model in use today is the relational data model. Well
known DBMS like oracle ,ms SQL server, DB2 & my SQL
support this model . hierarchical data models & network
data models, are used in industry there are traditional
model & they have more complerity . Oo dbms are
introduced in recent years in this information represented
in form of objects & combine capabilities with object –
oriented programming language.

19. Classification based on user numbers : DBMS can be classified
based on the number of users its supports . It can be single user
database system which can support one user at a time, or a multi
user data base which support multi user
Concurrency
Classification based on database distribution :
There are 4 main distribution systems for
database systems and these , inturn ,can be used to classify the
DBMS.
Centralized system : in centralized database system the DBMS
& database are stored at a single site that is used by several
other systems too.

20. Distributed database system :
in this the actual database & the
DBMS s/w are distributed from
various sites that are connected by
a compute network .
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21. • homogeneous distributed database system :it
uses THE same DBMS S/W from multiple site data
exchange between these varios sites can be handled
easily . For ex : library information system from same
vendor.
• Heterogeneous distributed database system : in
this different sites might use different DBMS but thre is
additional common s/w support data exchange b/w
these sites . For ex : library database systems machine
– readable catalogue (marc).