This document provides an introduction to database management systems (DBMS). It discusses the disadvantages of traditional file-based data management approaches, such as data redundancy and lack of data integrity. It then describes the key components of a database system, including the database itself, DBMS software, users, and administrators. Challenges of DBMS include security, data quality, and data integrity issues that must be addressed. The overall system structure partitions responsibilities between query processing and storage management components.

1. Introduction to Database
Management System

2. The Traditional Approach To Data
Management
– Create new
files for each
application
– Data
redundancy
– Data integrity

3. Disadvantages of File Processing
• Program-Data Dependence
– All programs maintain metadata for each file they
use
• Data Redundancy (Duplication of data)
– Different systems/programs have separate copies of
the same data
• Limited Data Sharing
– No centralized control of data
• Lengthy Development Times
– Programmers must design their own file formats
• Excessive Program Maintenance
– 80% of of information systems budget

4. Components of the database environment

5. Components of the
Database Environment
• CASE Tools – computer-aided software engineering
• Repository – centralized storehouse of metadata
• Database Management System (DBMS) – software
for managing the database
• Database – storehouse of the data
• Application Programs – software using the data
• User Interface – text and graphical displays to users
• Data Administrators – personnel responsible for
maintaining the database
• System Developers – personnel responsible for
designing databases and software
• End Users – people who use the applications and
databases

6. Disadvantages of DBMS
• Databases used in enterprises may involve additional
risks as compared to a conventional data processing
system in some areas
• Confidential, Privacy and Security : When
information is centralized and is made available to
users from remote locations, there is a possibility of
unauthorized users accessing sensitive information.
• It is necessary to take technical, administrative and
legal measures.

7. Disadvantages of DBMS
• Data Quality : Since database is accessible to users
remotely, adequate controls are needed to control users
updating data and to control data quality.
• With increased number of users accessing directly,
there is an opportunity for users to damage data.Unless
there are suitable controls, the data quality may be
compromised.
• Data Integrity : Since a large number of users cloud
be using a database concurrently, technical safeguards
are necessary to ensure that data remain correct during
operation.

8. Overall System Structure

9. Overall System Structure
• A database system is partitioned into
modules which handles different
responsibilities of over all system.
The functional components of a database
system are
 Query processor Component
Storage manager component

10. Query Processor Component
• DML Compiler : It translates DML statements
into a lower level instructions that the query
evaluation engine understands
• Embedded DML precompiler : It converts DML
statements embedded in an application program
into normal procedure calls in the host language.
• DDL Interpreter : It interprets DDL statements
and records them in a set of tables
• Query evaluation engine : It executes lower level
instructions generated by the DML compiler

11. Storage manager component
• It is an Interface between the data stored in the database and
the application programs and queries submitted to the
system.
• Authorization and Integrity manager : It tests for
satisfaction of integrity constraints and checks the authority
of users to access data.
• Transaction Manager : It ensures concurrent transaction
executions processed without conflicting.
• File manager : It manages the allocation of space on disk
and the data structures used to represent information.
• Buffer manager : Which is responsible for fetching data
from disk storage into main memory.

12. Application Architectures
Two-tier architecture: E.g. client programs using ODBC/JDBC to
communicate with a database
Three-tier architecture: E.g. web-based applications, and
applications built using “middleware”