Database Management System (DBMS) Notes
1.1 Drawbacks of Using Files to Store Data
1. Data Redundancy and Inconsistency
o Duplicate data across files leads to inconsistencies when
updates are not reflected everywhere.
2. Difficulty in Accessing Data
o File systems require custom programs to extract specific data,
which is complex and time-consuming.
3. Lack of Data Security
o File systems often lack robust security mechanisms to protect
data access.
4. Integrity Issues
o Ensuring data accuracy and consistency across a file system is
difficult without central controls.
5. Concurrency Problems
o File systems struggle to handle simultaneous access, leading
to potential data conflicts.
6. Limited Scalability
o Managing large volumes of data becomes cumbersome as the
system grows.
7. Data Isolation
o Data is scattered across multiple files in different formats,
making integration and retrieval complex.
1.2 Purpose of Database Systems
1. Reduce Redundancy:
o Centralized storage minimizes duplicate data across the
system.
2. Ensure Data Consistency:
o A single source of truth for all applications.
3. Facilitate Data Sharing:
o Multiple users can access data simultaneously without
conflicts.
4. Enhance Security:
o Controls who can access, modify, or delete data.
5. Maintain Data Integrity:
o Ensures data correctness via integrity constraints.
6. Enable Easy Access and Retrieval:
o Simplifies data queries using languages like SQL.
7. Improve Scalability and Efficiency:
o Handles increasing data volume effectively.
1.3 Definition of DBMS
A Database Management System (DBMS) is software designed to
manage, store, retrieve, and organize data efficiently. It provides users
with tools for adding, updating, and retrieving data using queries while
ensuring data security, integrity, and consistency.
Examples: MySQL, Oracle, PostgreSQL, MongoDB.
1.4 Comparison of File Processing System & DBMSn
Aspect File Processing System DBMS
Data High redundancy due to Redundancy minimized
Redundancy duplicate files. using central databases.
Data Difficult to ensure as updates Ensured with integrity
Consistency may not reflect everywhere. constraints.
Limited mechanisms to secure Robust security features
Data Security
data. available.
Concurrency Poor handling of simultaneous Excellent support for
Control access. concurrent users.
Integrity maintenance Centralized integrity
Data Integrity
depends on applications. checks enforced.
Aspect File Processing System DBMS
Ease of Complex; custom programs Simplified with query
Access are needed. languages like SQL.
Data Automated recovery
Limited or manual.
Recovery mechanisms available.
Less scalable with increasing High scalability and
Scalability
data volume. efficiency.
1.5 Users of DBMS
1. Database Administrators (DBA)
o Manage database systems, set up security measures, and
ensure optimal performance.
2. Developers
o Create applications using database systems to store, retrieve,
and process data.
3. End Users
o Access and interact with the database through applications
(e.g., customer using a banking app).
4. Data Analysts/Scientists
o Analyze data stored in the DBMS for insights and decision-
making.
5. Managers
o Use data from the database to monitor business operations
and make strategic decisions.
