DATABASE MANAGEMENT SYSTEM(DBMS) – CONCEPTS
Prof. Ashis Mitra
St. Xavier’s College, Kolkata
Recruiting Hiring Education
Employees Employees Retired
Primary HR Activities
DATA PROCESSING SYSTEM
A data processing system takes raw data and, through the power
of computer automation, produces information that a set of
program applications has validated. Information includes text,
arithmetic calculations, formulas and various other types of
information and data based on the computer system.
TYPES OF DATA PROCESSING
1. Serial Processing
2. Batch Processing
3. Real time processing
4. Online Processing
5. Centralised Processing
6. Distributed Processing
• 1. Serial Processing. It is a system in which only one step happens at a time (and so the steps
go in a series).
• 2. Batch Processing. It is used when there is a lot of transactions affecting a high percentage
of master file records and the response needed is not immediate, usually until the end of the
week or month. A good example of this in a large, national business would be payroll
processing, where nearly every master file record will be affected. The data is collected over a
period of time, then input and verified by clerks (verified means input by someone else and
then both inputs are compared by computer) and processed centrally.
• 3. Real-time processing. The waiting time from input to response is minimum. Unreasonable
However such fast systems are used in critical systems that control aircraft or the
manufacture of sensitive or dangerous compounds.
• 4. Online processing. It means users directly enter information online (usually, online,
in this case, means online to a central processor, rather than its modern connotation
of the Internet, but it could mean both), it is validated and updated directly onto the
master file. No new file is created in this case. Therefore, there is near immediate
input process, and output. It is like a booking with travel agents or over the Internet.
• 5. Centralized processing. It is processing performed in one computer or in a cluster
of coupled computers in a single location. Access to the computer is via "dumb
terminals," which send only input and receive output or "smart terminals," which add
screen formatting. All data processing is performed in the central computer.
• 6. Distributed Processing. The distribution of applications and business logic across
multiple processing platforms. Distributed processing implies that processing will
• occur on more than one processor in order for a transaction to be completed.
WHAT IS A DATABASE?
Database is a collection of interrelated data stored in a
database server; these data's will be stored in the form of
tables. The primary aim of database is to provide a way to store
and retrieve database information in fast and efficient manner.
DATABASE – MAJOR CHARACTERISTICS
• In database approach, a single repository of data is maintained that is
defined once and then accessed by many users.
• The database system not only contains data but it contains complete
definition or description of the database structure and constraints. These
definitions are stored in a system catalog, which contains the information
about the structure and definitions of the database.
• The information stored in the catalog is called the metadata, it describes
the primary database.
• Database allows multiple users to access the database at the same time
and sharing of data is possible.
• Database software allows data to be accessed in a variety of ways and
often, by using several programming languages.
Refers to the most common Database Operations:
Operations occur at all levels: Tables, Records, Columns
A DATABASE WITH MULTIPLE TABLES
Training Employee Pay Packet
Placement Perform. Mgt Pay Structure
is a model of structures of reality
supports queries and updates
modeling processes of reality
The purpose of database design is to create a
It is very important that the language used for
data representation supports abstraction.
There are three kinds of abstraction:
In a classification we form a concept in a way
which allows us to decide whether or not a
given phenomena is a member of the extension
of the concept.
Emp 1 Emp 2 Emp 3 Emp 4 Emp 5 Emp 6
In an aggregation we form a concept from existing
concepts. The phenomena that are members of
the new concept’s extension are composed of
phenomena from the extensions of the existing
In a generalization we form a new concept by
emphasizing common aspects of existing concepts,
leaving out special aspects
Jr. ExecutiveExecutiveSr. Executive
LEVELS OF ABSTRACTION
Physical level describes how a record (e.g., customer) is stored.
Logical level: describes data stored in database, and the
relationships among the data.
type Employee = record
name : string;
Designation : string;
EMP Code : integer;
View level: application programs hide details of data types. Views
can also hide information (e.g., salary) for security purposes.
A View is an individual’s picture of a database. It can be
composed of many tables, unbeknownst to the user.
It’s a simplification of a complex data model
It provides a measure of database security
Views are useful, primarily for READ-only users and are not always safe
for CREATE, UPDATE, and DELETE.
VIEW OF DATA
An architecture for a database system
USE OF A DATABASE MANAGEMENT SYSTEM
IN DESIGN AND APPLICATION
Evaluation Synthesis Release
Graphic Interface Language InterfaceINTERFACE
PEOPLE WORKING WITH DATABASES
communicate with each prospective
database user group in order to understand
develop a specification of each user group’s
information and processing needs
develop a specification integrating the
information and processing needs of the
document the specification
choose appropriate structures to
represent the information specified by the
choose appropriate structures to store the
information in a normalized manner in
order to guarantee integrity and
consistency of data
choose appropriate structures to
guarantee an efficient system
document the database design
implement the database design
implement the application programs to meet the program
test and debug the database implementation and the
document the database implementation and the application
Manage the database structure
participate in database and application
assist in requirement analysis
participate in database design and creation
develop procedures for integrity and quality of data
facilitate changes to database structure
seek communitywide solutions
assess impact on all users
provide configuration control
be prepared for problems after changes are made
DATABASE ADMINISTRATORS (CONT.)
Manage data activity
establish database standards consistent with data administration
establish and maintain data dictionary
establish data proponencies
work with data proponents to develop data access and modification
develop, document, and train staff on backup and recovery procedures
publish and maintain data activity standards documentation
DATABASE ADMINISTRATORS (CONT.)
Manage the database management system
generate database application performance reports
investigate user performance complaints
assess need for changes in database structure or
modify database structure
evaluate and implement new DBMS features
tune the database
Establish the database data dictionary
data names, formats, relationships
cross-references between data and application
(see metadata slide)
Parametric end users constantly query and update the
database. They use canned transactions to support standard
queries and updates.
Casual end users occasional access the database, but may
need different information each time. They use sophisticated
query languages and browsers.
Sophisticated end users have complex requirement and need
different information each time. They are thoroughly familiar
with the capabilities of the DBMS.