This document provides an overview of key topics covered in Unit 1 of a database management systems course, including: - The advantages and components of DBMS, data types, events, normal forms, and data dictionary. - Examples of common database applications like libraries, ATMs, and inventory management. - The differences between file systems and DBMS in terms of data storage and access. - The advantages of using a DBMS like data sharing, integrity, independence and security. - Stages of database normalization to reduce data redundancy and inconsistencies. - Converting class diagrams to normalized tables and merging object relations.

2. for 5th Sem.
B.Sc. (SAE5B) & BCA (SAZ5A)

3. Unit I
• Advantages and Components of a Database
Management Systems
• Feasibility Study
• Class Diagrams
• Data Types
• Events
• Normal Forms
– Integrity
– Converting Class Diagrams to Normalized Tables
• Data Dictionary

4. Examples of database application
• Computerized library systems
• Automated teller machines
• Flight reservation systems: For reservations and schedule
information.
• Inventory management Systems
• Banking: For customer information, accounts, loans and banking
transactions
• Universities: For student information, course registrations and
grades.
• Telecommunications: For keeping records of calls made, generating
monthly bills, maintaining balances on prepaid calling cards and
storing information about the communication networks.
• Sales: For customer, product and purchase information in any
industry.

5. DBMS vs. File System
File System
Loan_Processing
(Application Program)
Transaction Processing
(Application Program)
Fixed_Deposit_Processing
(Application Program)
Customer_Details.dat Customer_Loan.dat Customer_Fixed_
Deposit.dat
Customer_Transaction.dat
Figure 1.1: File System
Figure 1.2: The DBMS handle’s all requests for access to the database

6. File System Interface vs. DBMS Interface

7. Advantages of DBMS
• Centralized Management and Control.
• Reduction of Redundancies and Inconsistencies
• Data Sharing
• Data Integrity
• Data Security
• Data Independence
– Physical data independence
– Logical data independence
• Providing Storage Structures for Efficient Query Processing
• Backup and Recovery
• Some other advantages are:
– Reduced Application Development Time
– Flexibility
– Availability of up-to-date Information

8. Characteristics of Data in a Database
• Shared – Data in a database are shamed among different users and
applications.
• Persistence – Data in a database exist permanently in the sense the data
can live beyond the scope of the process that created it.
• Validity / Integrity / Correctness – Data should be correct with Respect to
the real world’s entity that they represent.
• Security – Data should be protected from unauthorized access.
• Consistency- whenever more than are database represents related real –
world valves, the valves should be consistent with respect to the
relationship.
• Non–redundancy – No two data items in a database should represent the
same real world entity.
• Independence – The three levels in the schema (internal, conceptual and
external) should be independent of each other so that the changes in the
schema at one level should not affect the other levels.

9. Stages of Normalization

10. Un normalized table
Project
Code
Project Name Project
Manager
Project
Budget
Emp.
No.
Employee
Name
Departm
ent No.
Department
Name
Hourly
Rate
PC010 Banking Mrs. Narayani 100000 101 Viji D03 Database 21.00
102 Ambika D02 Testing 16.50
103 Vicky D01 IT 22.00
PC011 ERP Mrs. Sasikala 200000 104 Shakthi D03 Database 18.50
105 Shalini D02 Testing 17.00
106 Fathima D01 IT 23.50
PC012 ecommerce Mrs. Kamala 300000 107 Vidya D03 Database 21.50
108 Amirtha D02 Testing 15.50
109 Padma D01 IT 20.50

11. Issues in Unnormalized table:
• It is not possible to uniquely retrieve a record
for example Employee 102.
• If you want to update Department No. D03 to
D04 you have to update all the records,
otherwise it leads to Data inconsistency
• It is not possible to count the no. of records in
the database
• Duplicate records such as Dept. Name, Dep.
No occupy space on the storage devices

12. Advantages of Normalized forms
• Ease of use
• Flexibility
• Precision
• Security
• Reliability
• Ease of Implementation.
• Clarity

13. Converting Class Diagrams to
Normalized Tables
• Translate the classes
• Translate the relationships
• Merge object relations

14. Data Dictionary

15. Unit II
• Query Basics
• Computation Using Queries
• Subtotals and GROUP BY Command
• Queries with Multiple Tables
• Subqueries
• Joins
• DDL & DML
• Testing Queries