Module 3 Object Oriented Data Models Object Oriented notations

ER Diagramming Models for OO Relationships DOEACC B-Level OODBMS 2011 Taher S. 3.Object Oriented Data Model

Models as Analysis and Design Methods Object technology has many different methodologies to help analyze and design computer systems. In most cases these methodologies are very similar, but each has its own way to graphically represent the entities. To understand and use these methodologies would become difficult, if not impossible, for all projects. If need be, it is possible to use concepts from one method with concepts from another technique, basically creating your own object development technique. The most important point is to remember is that the final outcome is what really matters, not the choice of one analysis technique over another technique.

Methodologies: Coad-Yourdon Developed in the late 80’s Five-step analysis method Shlaer-Mellor Developed in the late 80’s Emphasizes modeling information and state, rather than object interfaces OMT Notation UML Notation Booch Notation

Coad- Yourdon Their methodology is based on a technique called "SOSAS", which stands for the five steps that help make up the analysis part of their methodology. Following analysis, Coad and Yourdon define four parts that make up the design part of their methodology. The steps of system design are: The problem domain component - This will define the classes that should be in the problem domain. The human interaction component - These steps defines the interface classes between objects. The task management component - This is where system-wide management classes are identified. The data management component - This design step identifies the classes needed for database access methods.

Coad Subject Diagrams Gen- Spec Relationship Whole- Part Relationship

Shlaer- Mellor Shlaer-Mellor methodology has its primary strength in system design and is considered somewhat weak on analysis. The Shlaer-Mellor methodology includes three models; the information model, the state model, and the process model. Developed by Sally Shlaer and Stephen Mellor, this system is also known as the Object-Oriented Systems Analysis (OOSA). OOSA contains a wide variety of diagrams including: a domain chart diagram, object information model diagram, state transition model, an action data flow diagram, a class diagram, and a class structure chart.

OMT Notation James Rumbaugh's Object Modeling Technique (OMT) is one of the precursors to the Unified Modeling Language (UML). There are three main diagrams in OMT: object, dynamic, and functional. Object View Diagrams The OMT object model illustrates the static relationship among classes and objects in a system. This diagram is similar to the UML object and class diagrams. The OMT Dynamic Diagram Notations The OMT dynamic models resemble UML sequence and UML statechart diagrams. The OMT Static Diagram Notations The OMT static models consist of multiple data flow diagrams.

OMT- Other Diagrammatic Notations Objects: Draw an object using a rectangle with rounded corners. Attributes must have values assigned to them. Linked Attribue: To describe the properties of a link or association, you can use an arc to attach an attribute to the relationship.

OMT- Other Diagrammatic Notations Qualified associations: Qualifier used to distinguish among the set of objects in the many end of the association. The qualified association is unique to the OMT notation. Place the qualifier box at the end of the association, near the class you want to qualify.

Booch Notation Grady Booch's Object-Oriented Design (OOD), also known as Object-Oriented Analysis and Design(OOAD), is a precursor to the Unified Modeling (UML). The Booch method includes six types of diagrams: class, object, state transition, interaction, module, and process. Booch Class and Object Diagrams: Classes: Illustrate classes using a cloud shape with a dashed border. Objects: Draw objects using a cloud shape with a solid border.

Booch Class and Object Diagrams: Class Adornments: Use adornments to provide additional information about a class. You can create an adornment notation using the basic triangle shape. Place a letter inside the triangle to represent the following: A - Abstract. An abstract class cannot be instantiated because it represents a wide variety of object classes and does not represent any one of them fully. For example, mammal could be thought of as an abstract class. F - Friend. A friend class allows access to the nonpublic functions of other classes. S - Static. A static class provides data. V - Virtual. A virtual class is a shared base class, the most generalized class in a system.

Booch Class and Object Diagrams: A Booch class Diagram

Module 3 Object Oriented Data Models Object Oriented notations

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Module 3 Object Oriented Data Models Object Oriented notations