1. EER vs. UML Terminology EER Diagram Entity Type Entity Attribute
Domain
Composite Attribute
~ [Derived Attribute]
Relationship Type
Relationship Instance
Cardinality & Participation
UML Class Diagram
Class
Object
Attribute
Domain
Structured Domain
Operation
Association
Link
Multiplicities
UML

2. EER Example Participation Department 1 Is In N Cardinality Employee N
DNAME
Cardinality
Employee N
NAME P#
Assigned To M
FNAME
LNAME
Project
%TIME
PNAME
UML

3. Diagrams EER vs. UML Employee Employee … Entity Type vs. Class
FNAME
LNAME
NAME
Attributes
Employee E#
NAME: NameDom
FNAME
LNAME …
Methods
Structured
Domain
Entity Type vs. Class
Attribute
Composite Attribute vs. Structured Domain
UML

4. EER vs. UML Complete Diagram
Department D#
DNAME …
EER vs. UML Complete Diagram
1..1
Min participation (0 or some int n: n>0)
0..* D#
Employee E#
NAME: NameDom
FNAME
LNAME …
Department
Employee E#
FNAME
LNAME
NAME Is In 1
DNAME N
Max Cardinality N P#
0..*
Assigned To
AssignedTo
%TIME M
0..*
Project
Project P#
PNAME …
%TIME
PNAME
UML

5. EER Derived Attributes - Include in Department the average salary of the employees in the department.
Member Of
Employee
Department
Salary
AvgSal
Class
Method
Department D#
DNAME
AvgSal
UML

6. EER Multi-valued Attributes
as Entity
Major N
Has
Major 3
Student
Major
Student
Major_Program
UML
Student …
Major_Program
Major …
0..*
0..3
UML

7. Weak Entities EER Weak Entity Name Employee Dependents Of Dependent
SSN 1 N
Dependent
Name
Employee
SSN …
UML
Qualified Association
UML

8. Aggregations Location Location Project Department No No Name No Name…
Department
Name No …
0..*
1..1
Location
Name
1..*
0..*
UML

9. Example: University Database
Superclasses & Subclasses
Generalization & Specialization
Inheritance d
disjoint o
overlap
total
partial U
superclass
subclass
EmpID
Salary
SSN
Employee
Degree
Program U
Person o U
Grad Student
Name U
Student d U
Superclass instance must always exist.
Undergrad Student
Major
Dept
Class
UML

10. UML Superclass/Subclass Inheritance
EER UML
disjoint
overlapping
Employee
EmpID
Salary … d o
Person
SSN
Name …
GradStudent
DegreeProgram …
Student
MajorDept …
UndergradStudent
Class …
UML

11. Object-Oriented Approach Motivation
Object-Oriented Databases (OODB)
Add persistence to object-oriented programming languages
Object Relational Databases (ORDBMS)
Add user-defined methods to relational databases
Allow grouping of relations into more complex “objects”
UML

12. Relational is Good For Fixed format data Transaction processing:
simple short transactions
Concurrency control
Recovery from crashes
Query processing and Query optimization
relational algebra and mathematical logic operations.
UML

13. Problems The relational model has no notion of a single object.
Context with the real world
e.g., spatial context.
Aggregation functions may be desired
The notion of re-use cannot be exploited
There may also be versions or variant configurations
i.e variations of the same design.
UML

14. Problems With the Relational Model - 1
Nonhomogeneous collection of design objects.
Data Types: images, matrices, vectors; variable length.
Temporal and/or spatial data.
Many data types; few instances of each type.
UML

15. Problems With the Relational Model - 2
Schemas evolve during design.
Long running transactions: "checkout a design".
Versions; design log.
UML

16. Problems With the Relational Model - 3
Functions needed:
Making a design permanent,
Releasing design to production,
Archiving design,
etc.
Library of design objects:
minimize redundancy.
UML

17. Object-Oriented Concepts - 1
Complex Objects:
sets,
bags,
lists,
arrays,
tuples.
UML

18. Object-Oriented Concepts - 2
Object Identity: identify by object id (oid) rather than by an attribute value, never changes.
Encapsulation: Operations and Data available to user.
Implementation hidden. No other operations available.
UML

19. Object-Oriented Concepts - 3
Types and/or Classes:
Type:
Interface and Implementation.
Types declared, checked at compile-time
Class:
Instances created at run-time
UML

20. Object-Oriented Concepts - 4
Class or Type Hierarchies:
Inheritance: both data and function
example: student: undergraduate, graduate
Overriding, overloading, and late binding:
Polymorphism
UML

21. Object-Oriented Concepts - 5
Computational Completeness:
Extensibility:
Means to define new types.
User types not distinguished from system types.
Persistence:
Not present in OO programming languages.
Should be implicit not explicit.
UML

22. Object-Oriented Concepts - 6
Secondary Storage Management:
Concurrency:
Recovery:
Ad Hoc Query Facility:
UML

23. Review: Object State (value) Behavior (operations)
Signature or interface: operation name and arguments
Method or body: implementation
Identified by unique Object Identifier (OID)
UML

24. Class Group of similar objects Class hierarchies
Inheritance
Persistence must be specified explicitly
Via entry point
Via reachability
UML

25. Type Hierarchies and Inheritance (EER – superclass/subclass relationship)
PERSON: Name, Address, Birthdate, Age, SSN
EMPLOYEE: subtype-of PERSON: Salary, HireDate, Seniority
STUDENT: subtype-of PERSON: Major, GPA
EMPLOYEE: Name, Address, Birthdate, Age, SSN,
Salary, HireDate, Seniority
STUDENT: Name, Address, Birthdate, Age, SSN,
Major, GPA
UML

26. Object Data Management Group (ODMG)
Object Model
Object Definition Language (ODL)
Object Query Language (OQL)
Bindings to object-oriented programming languages
C++, Java, Smalltalk
UML