1. Extended E-R Model: Basic Symbols
Strong Entity Set
Associative Entity Set
Weak Entity Set
Attribute
Association Relationship Set
Multi-Valued Attribute
Identifying Relationship Set
Derived attribute

2. Extended E-R: Relationship Cardinality
Mandatory One
Mandatory Many
Optional One
Optional Many

3. Relationship Set: Cardinality
Maximum Cardinality for Offering
Maximum Cardinality for Course
Course
Has
Offering
(1:1)
(0:N)
Course-NO
C-Des
Credit-Hour
Offer-NO
Off-Location
Off-Time
Minimum Cardinality for Offering
Minimum Cardinality for Course

4. Graphical Notations for Cardinality
1: One
M: Many 1 M
EMPLYEE
DEPARTMENT
Works-for
: One
EMPLOYEE
DEPARTMENT
Works-for
: Many
EMPLOYEE
DEPARTMENT
Works-for
Many
One
EMPLOYEE
: One
: Many
DEPARTMENT
Works-for

5. ER Diagram: An Example Sends SUPPLIER Supplies CUSTOMER Includes
SHIPMENT
ITEM
Submits
KEY
Relationship
Used_in
Entity
Cardinalities
Mandatory One
Requests
PRODUCT
ORDER
Mandatory Many
Optional One
Optional Many

6. Weak Entity: An Example
Last_Name
First_Name
Middle_Initial
Date_of_Birth
Employee_Name
Employee_ID
Dependent_Name
EMPLOYEE
Has
DEPENDENT

7. Unary Relationship: Examples
Marries
PERSON
One-to-one
Manages
EMPLOYEE
One-to-many

8. Binary Relationship: Examples
EMPLOYEE
Assigns
PARKING PLACE
One-to-One
PRODUCT LINE
Contains
PRODUCT
One-to-Many
STUDENT
Registers_for
COURSE
Many-to-Many

9. Ternary Relationships: Example
Supplies
VENDOR
WAREHOUSE
PART
Shipping_mode
Unit_cost

10. Composite Attribute Address City State Street_Address Postal_Code
DB Design Question: Should we model address as a simple or composite attribute?

11. Multi-Valued versus Derived Attribute
EMPLOYEE
Date_Employed
Years_Employed
Employee_ID
Employee_Name
Address
Skill

12. Specialization/Generalization Relationships: Disjointness and Completeness Constraints
PERSON
Overlapping and Partial Coverage
IS-A
(O,P)
DOCTOR
PATIENT
Disjoint and Total Coverage
IS-A
(D,T)
IN-PATIENT
OUT-PATIENT