The document discusses entity relationship data modeling, which visually represents how data is related. It defines key concepts like entities (objects like people or places), attributes (properties of entities), relationships (connections between entities), and relationship types (one-to-one, one-to-many, many-to-one, many-to-many). Symbols are used to depict these elements on an entity relationship diagram, including rectangles for entities, ovals for attributes, diamonds for relationships, and lines for links. Weak entities, composite attributes, and recursive relationships are also summarized.

1. Entity Relationship Data Model
Mohd Tousif

2. Logical Data Model - ERD
Visual representation of data that describes how data
is related to each other. Symbols used
Entity – rectangle
Attribute – Oval
Relationship – diamond
Link - line

3. Entity
Entity : Object that is involved in the Enterprise and
that can be distinguished from other object. Can be
a person / place / object .
Ex : Student , Course
Student

4. Weak Entity
•An entity that depends on other entity. Weak
entity does not have key attributes of its own.
Represented by double rectangle
PaymentLoan

5. Attribute
•An attribute describes a property / characteristic
of an entity.
Name

6. Key Attribute
•Represents the main characteristics of an entity.
Used to represent Primary keys.
id

7. Composite Attribute
•An attribute which have its own attributes.
Address
city state pincode

8. Relationship
•To establish relation between entities.
studies

9. Types of Relationship
• Two types of relationships
Binary
Recursive

10. Binary Relationship / Cardinality
• Relationship between two entities. Each entity in
relationship can participate in zero, one or more
than one instance of that relationship. It is of four
types:
One – One
One – Many
Many – One
Many - Many

11. •One – One
1 1

12. •One – Many
1 *

13. •Many – One
1*

14. •Many – Many
**
NM

15. Recursive Relationship
Employee
managed
manages

16. Course
Participant
learnt
1
*
Class
Enrolls
**
*
Taken
1
Faculty
Evaluation
handled1
*
handles
*
*
rates
1
*
*

17. Q & A

18. Thank You!