The document discusses relational database management systems (RDBMS). It describes some key disadvantages of file processing systems like data redundancy and inconsistency. An RDBMS uses a database, DBMS, and application programs to allow for data storage in tables/relations with rows and columns. The document outlines important aspects of RDBMS like data models, database languages, database administrators, keys, relationships, and normalization.

1. Relational Database Management System

2. Relational Database Management System
DATA
DATABASE
DBMS/RDBMS
Information

3. File Processing System
Database
(Information in
Files Format)
Application
Programs
(Programs
Written in C
Pascal etc.)
File System
(Data
Structure
File Handling)

4. Disadvantages of FPS
Data Redundancy and Inconsistency
 Difficulty in accessing data
Data isolation
Integrity Problems
Atomicity Problems
Concurrent-access anomalies
Security Problems

5. Data Redundancy and Inconsistency
Name Address
ABC Bhiwani
DEF Delhi
AccNo Name Address
1002 ABC Bhiwani
1005 DEF Jaipur
Customer Information Saving Account

6. Difficulty in accessing data
Application
Programs
(Programs
Written in C
Pascal etc.)
File System
(Data Structure
File Handling)
Database
(Information Storage
in Files Format)
Manager
Requirement

7. Requirements of a DBMS
• A mechanism for specification of data and its dependencies
(Integrity Constraints) in an integrated fashion.
• Prevention of redundancy and inconsistency.
• Provision of adequate security and access-rights.
• Mechanism for concurrency control.
• Mechanism for recovery from failure. Additionally any DBMS must provide
• Schemes for specification of procession rules or application Programs.
• Efficient techniques for storage and retrieval of data from the secondary

8. D
B
M
S
File
Manager Secondary
Storage
A DBMS has two major components, namely
Structure of Database is called Database Schema.
Instance, which is a state of the database with the actual data loaded.
A set of software tools/programs which access, update and
process the database, called the query and update-mechanism.

9. Data Independence
The ability to modify a schema definition in one level without affecting a
schema definition in the next higher level is called data independence.
Physical data independence Logical data independence
Create table emp
(empno number(10),------,--
------);

10. Data Models
A Data Model is a mechanism for describing the data, their interrelationships
and the constraints.
Object-based Conceptual models.
Entity-Relationship model
Record-based models.
Relational Model
Network Model
Hierarchical Model
Physical data models.

11. The E-R Model
Entities : An entity is a distinct clearly identifiable object of the database e.g Book Attribute :
Each Entity is characterized by a set of attributes e.g. Acc.No. Entity Set : Set of all entities
having attributes of the same type. Relationships : A relationship is a mapping between entity
sets.
Acc_No Title
Acc_No Card_No Name
Book Borrowed_By USERS
____

12. Hierarchical Model
This is special kind of a network model where the relationship is
essentially a tree-like structure.
Hospital
Wards Units
Patient Doctors Nurses Cardiology Skin

13. Physical Data Models
Physical data models are used to describe data at the lowest level. In contrast to logical
data models, there are few physical data models In use. Two of the widely known
ones are the Unifying model and frame-Memory model.
Database Languages
Database Languages
Data-Definition Data-Manipulation Data-Control
Create Table Test
(
Title
Varchar2(20),
-------- ,-------);
Update
Insert
Delete
Query
GRANT Connect,
Resource TO x
User

15. Database Administrator
Roles of DBA
• Schema Definition
• Storage structure and access-method definition
• Schema and Physical-organization modification
• Granting of authorization for data access
• Integrity-constraint specification
Terms
• Simple and Composite Attributes
• Single-valued and Multivalued Attributes
• Null Attributes
• Derived Attributes
• Existence Dependencies
•Weak Entity Set and Strong Entity Set

16. Weak Entity Set

18. Keys
Keys
Candidate Key Secondary Key Foreign Key
Primary Key Alternate Key
Composite Key

19. Mapping Cardinalities
Mapping cardinalities, or cardinality ratios, express the number of entities to which
another entity can be associated via a relationship set. For a binary relationship set R
between entity sets A and B, the mapping Cardinality must be one of the following
A B A B
One to One One to Many

20. A B A B
Many to One Many to Many

21. More on E-R Diagrams
Company
Owns Multiple Relationships between Leased
Same entity set
Vehicle
Manager
Staff Reports to
Subordinate
Circular Relationship

25. Specialization & Generalization

28. The Relational Algebra
The relational algebra is a procedural query language.
Fundamental Operations
select (unary)
project (unary)
rename (unary)
Fundamental Operations
cartesian product (binary)
union (binary)
set-difference (binary)
Several other operations, dened in terms of the fundamental operations:
set-intersection
natural join
division
assignment
Operations produce a new relation as a result.

29. Formal Definition of Relational Algebra

30. The Select Operation

31. The Project Operation

32. The Cartesian Product Operation

33. The Union Operation
The Set Difference Operation

34. Relational Calculus
Relational Calculus is a nonprocedural Query language
Tuple Relational Calculus
Uses Tuple variables which take values of an entire tuple
Domain Relational Calculus
Uses Domain variables which takes values from an attribute

35. Tuple Relational Calculus

36. Normalization
Normalization is a process of removing redundancy using functional Dependencies.
To reduce redundancy it is necessary to decompose a relation into a number of smaller relations.
There are several normal Forms.
-First Normal Form (1 NF)
-Second Normal Form (2 NF)
-Third Normal Form(3 NF)
-Boyce-Codd Normal Form (BCNF)

37. First Normal Form (1NF)
This normal form says that all attributes are simple.
An attribute is said to be simple if it does not contain any subparts.
An attributes which contains subparts is called complex attributes.
F_name L_name
C_addr
City State Zip
Name

38. Second Normal Form (2NF)
A relation is said to be in 2NF if it is in 1NF and
All non-prime attributes are fully functionally dependent on candidate key
Consider a relation savings_deposit having the fol owing structure:-
Saving_deposit (name, addr, acc_no, amt )
With the fol owing FDs :
name Add
name, acc_no addr
Here [name, acc_no ] is the candidate key and addr and amt are the non
prime attributes.
Among the non-prime attributes amt depends on [name, acc_no ] whereas
addr depends
on name only.
Note that due to FD name
Address causing redundancy.
addr every tuple with the same name will contain the same
This redundancy arises because a non-prime attribute like address is
dependent on an attribute

39. Third Normal Form (3NF)
A relation is said to be in 3NF and non-prime attributes are not dependent
On each other.
Consider the relation –
s_by ( s_name, item, price, gift_item )
With FDs
s_name, item price
Price gift_item
Here al prime attributes are ful y functional dependent on candidate
keys, the
Non-prime attribute gift-item is also ful y functional dependent on the
non-prime
Attribute price. This create redundancy because every price value
there is a fixed
Gift item.
We shal have to impose the additional restriction that no non-prime
attribute can
Be functional y dependent on another non-prime attributes.

40. Boyce-Codd Normal Form (BCNF)