Describe s the Database Models

1. Types of
Database Models

2. Data Model
 Describes structure of the database.
 Aim is to support the development of information
systems by providing the definition and format of
data.
 Classification:
 1. High-Level Model
 2. Representation Model
 3. Low-Level Model

3. 1. High-Level Model
• Ensures data requirement of the users.
• Not concerned with representation, but
it‘s a conceptual form.
• Three Impotant terms:
a)Entity: - Any object, exists physically or conceptually.
b)Attribute:- Property or characteristic of entity.
c)Relationship:- Association or link b/w two entities.
• These 3 terms make Entity-Relationship Model.

4. Widely accepted and adapted graphical tool
for data modeling.
Introduced by Chen in 1976.
Graphical representation of
entities and their relationships in
a database structure.
Entity-Relationship (E-R) Model

5. Entity-Relationship (E-R) Model
College Principal
College
Student C
Student A
Student B
College 3
College 2
College 1
Course C
Course B
Course A
Student CourseAdmission
Stud_Name Stud_Roll No Course_Id Course_Name
Relationships
E-R diagram

6. •Advantages
–Exceptional conceptual simplicity
–Visual representation
–Effective communication tool
–Integrated with the relational data
model
•Disadvantages
–Limited constraint representation
–Limited relationship representation
–No data manipulation language
–Loss of information content

7. 2. Representation Model
- Representation of data stored inside a database.
- Describes the physical structure of the database.
- It uses the concepts which are close to the end-users.
- Classification:
a. Hierarchical
b. Relational
c. Network

8. a. Hierarchical Database Model
• Developed by IBM, is the Oldest database model.
• Represented using a tree-diagram.
(Parent-child relationship)
• Each box is called a "Node"
• The nodes represent a record type.
• A line connecting nodes represent
the link.
Director
Manager
(Market.)
Man
(Sa
ager
les)
Manager
(HR)
Area
Manager
1
Area
Manager
2
Area
Manager
3
Sales Exe.
1
Sales Exe.
2
Sales
Representative

9. Cont…
• Parent-child type is suited for One-to-many
relationship between two entities.
• But difficult to implement
many-to-many relationship.
e.g.:
IMS system from IBM.
Director
Manager
(Market.)
Man
(Sa
ager
les)
Manager
(HR)
Area
Manager
1
Area
Manager
2
Area
Manager
3
Sales Exe.
1
Sales Exe.
2
Sales
Representative

10. Advantages:-
–Conceptual simplicity
–Database security
–Data independence
–Database integrity
–Efficiency
Disadvantages:-
–Complex implementation
–Difficult to manage
–Lacks structural independence
–Complex applications programming and use
–Implementation limitations
–Lack of standards

11. b. Relational Database Model
• Simplest and the most common model.
• Developed in 1970 by E.F. Codd, it became commercial
in the 80s.
• Data elements are stored in
different tables made up of
rows and columns.
Roll No Name Surname Section
1001 Rajkumar Tomar D
1002 Rajkumar Singh D

12. Relational Database Model(Cont)
• Terminologies:
-Data Values: alphanumeric raw data (Rajkumar)
-Columns: fields (item or object that holds the data)
-Rows: record (a group of data for related field)
-Table: collection (all records & fields)
-Key: identifier (uniquely identifies a row in the
table. It can be value of a single or multiple column.
e.g.:
DB2, ORACLE, SQL Server.
Roll No Name Surname Section
1001 Rajkuma r Tomar D
1002 Rajkuma r Singh D

13. • Advantages
–Structural independence.
–Improved conceptual simplicity.
–Easier database design, implementation, management,
anduse.
–New technology performance power and flexibility with
multiple data requirement capabilities.
–Data security (strong privacy)
–Powerful database management system.
• Disadvantages
–Substantial hardware and system
software overhead.
–Can facilitate poor design and implementation.
–May promote “islands of information” problems.

14. c. Network Database Model
• Represented using a Data-Structure
Diagram.
• Boxes represents the records & lines the
links.
• Based on
"owner-member relationship"
• Can represent one-to-one
and many-to-many as
well.
Teacher 1 Teacher 2 Teacher 3
Course A Course B Course C
Student 1 Student 2 Student 3

15. • Advantages
–Conceptual simplicity
–Handles more relationship types
–Data access flexibility
–Promotes database integrity
–Data independence
• Disadvantage
–Difficult for first time users
–System complexity
–Lack of structural independence

16. DatabaseModels:-
1) Network model
2) Hierarchical model
3) Relational model
4)Entity-Relationship data model
(mainly for database design)
5)Object-based data models (Object
oriented and Object-relational)
6) Semi-structured data model (XML)

17. Object-based datamodels
Object-oriented
&
Object-relational

18. The Object OrientedModel
•Semantic data model (SDM) developed by Hammer
and McLeod in 1981
•Modeled both data and their relationships in a
single structure known as an object
•Basis of object oriented data model (OODM)
•OODM becomes the basis for the object oriented
database management system (OODBMS)

19. Object Oriented DataModel—
Basic Structure• Object: abstraction of a real-world entity.
• Attributes describe the properties of an object.
•Objects that share similar characteristics are
grouped in classes.
• Classes are organized in a class hierarchy.
•Inheritance is the ability of an object within the class
hierarchy to inherit the attributes and methods of classes
above it.

20. • Diagram:-

21. •Advantages
–Adds semantic content
–Visual presentation includes semantic content
–Database integrity
–Both structural and data independence
•Disadvantages
–Slow pace of OODM standards development
–Complex navigational data access
–Steep learning curve
–High system overhead slows transactions
–Lack of market penetration

22. Object-Relational DataModel
• The new, extended version of relational
database technology called object-
relational database management systems
also known as ORDBMS.
• An ORDBMS supports an extended form of
SQL called SQL3 that is still in the
development stages. The extensions are
needed because ORDBMSs have to support
ADT's.

23. Advantages
• large storage capacity,
• access speed
• manipulation power of object databases.
• Disadvantages
• The architecture of ORDBMS is not
appropriate for high-speed web
applications.
• ORDBMS are set to conquer the database
market.

25. Thanks 

26. Introduction to File
https://www.slideshare.net/San
thiNivas/introduction-to-file-
system
File System Vs Database 
https://www.slideshare.net/Santh
iNivas/file-system-vs-database

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