1. Chapter 3: Modeling Data in the Organization
Database for Information System Fall 2012 Mr. Mohammed Rafiq Section: 201 Chapter Presentation (10%)
Presented by: Farah AlSharif
Chapter 3: Modeling Data in the Organization

2. Outline The Definition and Characteristics of Business Rule Data
ER- Modeling Diagram
The Components of Entity Relationship Diagram
Types of Entities
Types of Attributes
Relationship Degrees
Example of ERD

3. What is a Business Rule? What is a business rule?
A business rule defines or constrains one aspect of a business that is intended to assert business structure or influence the behavior of your business.
Business Rules Characteristics
Atomic
Business statements
Declarative
Constraining
Expressed in natural language
Traceable

4. What is a Data?
Data: Facts and statistics collected together for reference or analysis.
Good Data Name Characteristics
Related to business, not technical, characteristics
Meaningful and self-documenting
Unique
Readable
Composed of words from an approved list
Repeatable
Follows standard syntax

5. What is ER-Modeling?
ER-modeling is a data modeling technique used in software engineering to produce a conceptual data model of a information system
Diagrams created using this ER-modeling technique are called:
Entity Relationship Diagram
ERD typically consists of four different graphical components:
Entities
Attributes
Relationships
Cardinalities

6. What is ER-Modeling? (continued)
Entities:
Entity instance–person, place, object, event, concept (often corresponds to a row in a table)
Attributes:
property or characteristic of an entity or relationship type (often corresponds to a field in a table)
Employ
Project
Employee-ID
Project-Name

7. Types of entities Exist independently of other types of entities
Strong entities
Exist independently of other types of entities
Has its own unique identifier
Identifier underlined with single line
Weak entity
Dependent on a strong entity (identifying owner)…cannot exist on its own
Does not have a unique identifier
Partial identifier underlined with double line
Entity box has double line
Associative Entity
All relationships for the associative entity should be many.
The associative entity could have meaning independent of the other entities.
Strong
Weak
Weak
Associative

8. Types of attributes:
Key Attributes – Uniquely identify instance of a corresponding entity set
Multivalued Attributes – attributes that may contain multiple values
Simple Attributes – Cannot be subdivide
Composite Attributes – attributes that contains meaningful component parts
Derived Attributes – attributes whose values are computed from other data in the database

9. Relationships & Cardinalities
Relationship instance–link between entities (corresponds to primary key-foreign key equivalencies in related tables)
Cardinality:
Cardinality constrains-the number of instances of one entity that can or must be associated with each instance of another entity
Minimum Cardinality
If zero, then optional
If one or more, then mandatory
Maximum Cardinality
The maximum number
Employ
Relationship

10. Degrees of a Relationship
A degree of a relationship is the number of entity types that participate in it
The Degrees are:
Unary Relationship
One entity related to another of the same entity type
Binary Relationship
Entities of two different types related to each other
Ternary Relationship
Entities of three different types related to each other

11. Degrees of a Relationship (continued)
Binary
Unary
Ternary

12. ERD Example

13. References
Jones, B. (2010, December 5). E-R Diagrams. University of Missouri- St. Louis. Retrieved December 9, 2012, from
Interpreting Entity-Relationship Diagrams. (n.d.). Welcome to Phil Block's Personal Web Site. Retrieved December 9, 2012, from relationship_diagrams.html

14. Any Questions?