DBMS

DataBase Management System

• Unit 1 Introduction
• Unit 2 Relational Data Model
• Unit 3 Database Design and Normalisation
• Unit 4 Transaction Processing Unit
• Unit 5 Concurrency Control Techniques

Unit 1 Introduction

What is DBMS?

• Software used to manage database
• Example, MySQL & Oracle (Commercial DB)
• Provides interface to perform operations like:
  • Creation of Database
  • Storage of Data
  • Updation of Data
  • Creation of table in Database
• Provides protection and security to DB
• Maintains data consistency (in case fo multiple users)

Tasks Allowed using DBMS

1. Data Definition: Creation, modification, removal of DB objects
2. Data Updation:
3. Data Retrieval:
4. User Administration:

Advantages of DBMS

1. Database Redundancy:
2. Data Sharing:
3. Easy Maintenance:
4. Time Reduction
5. Backup
6. Multiple User Interface:

Disadvantages of DBMS

1. Cost of h/w & s/w:
2. Size:
3. Complexity:
4. Higher impact of failure:

DB Users: Use and take benefits of DB

Types of DB Users

1. Application Programmers:
2. Sophisticated Users:
3. Specialized Users:
4. **

Super vs Candidate vs Primary Key

Super Key	Candidate Key	Primary Key
Attribute	Minimal set of super key	Minimal set of attributes that uniquely identifies rows in a relation
Can be null	Can be null	Cannot be null

Generalisation

• Process of combination of 2 lower level entities to form higher level entity
• Bottom up approach
• Used to emphasise similarities among lower level entity sets & to hide the differences

Specialization

Aggregation

Unit 2 Relational Data Model

Relational Model

1. Collection of Conceptual tool For describing data, data relationships, data semantics and consistency constraints.
2. Primary data model for commercial data processing applications.
3. uses collection of tables to represent both data and the relationships among those data.
4. Each table has multiple columns and each column has a unique name.

Unit 3 Database Design and Normalisation

Unit 4 Transaction Processing Unit

Unit 5 Concurrency Control Techniques

Oracle

SQL Plus

• Front end tools for Oracle
• Looks similar to DOS
• White background like Notepad
• Allows typing in our statements

SQL Net

SQL Loader