Presentation is loading. Please wait.

Presentation is loading. Please wait.

EER vs. UML Terminology EER Diagram Entity Type Entity Attribute

Similar presentations

Presentation on theme: "EER vs. UML Terminology EER Diagram Entity Type Entity Attribute"— Presentation transcript:

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

Download ppt "EER vs. UML Terminology EER Diagram Entity Type Entity Attribute"

Similar presentations

Ads by Google