1. Copyright Irwin/McGraw-Hill 1998 1 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley An Introduction to Object Modeling  An Introduction to Object Modeling  The approach of using object modeling during systems analysis and design is called object-oriented analysis.  Object-oriented analysis (OOA) techniques are used to (1) study existing objects to see if they can be reused or adapted for new uses, and to (2) define new or modified objects that will be combined with existing objects into a useful business computing application.  The object-oriented approach is centered around a technique referred to as object modeling.  Object modeling is a technique for identifying objects within the systems environment, and the relationships between those objects.

2. Copyright Irwin/McGraw-Hill 1998 2 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley System Concepts for Object Modeling  Objects, Attributes, Methods, and Encapsulation  The object-oriented approach to system development is based on the concept of objects that exist within a system’s environment.  Objects are everywhere  Webster’s Dictionary definition of an object.  Something that is or is capable of being seen, touched, or otherwise sensed.  In object-oriented approaches to systems development the definition of an object is as follows:  An object is something that is or is capable of being seen, touched, or otherwise sensed, and about which users store data and associate behavior.

3. Copyright Irwin/McGraw-Hill 1998 3 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley System Concepts for Object Modeling  Objects, Attributes, Methods, and Encapsulation  The types of objects may include a person, place, thing, or event.  An employee, customer, vendor, and student are examples of person objects.  A particular warehouse, regional office, building, and room are examples of place objects.  A product, vehicle, equipment, video tape, or a window appearing on a users display monitor are examples of thing objects.  An order, payment, invoice, application, registration, and reservation are examples of event objects.

4. Copyright Irwin/McGraw-Hill 1998 4 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley

5. Copyright Irwin/McGraw-Hill 1998 5 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley System Concepts for Object Modeling  Object/Class Relationships  Objects and classes do not exist in isolation.  The things they represent interact with, and impact one another to support the business mission.  Thus there is an object/class relationship. An object/class relationship is a natural business association that exists between one or more objects/classes.  For example, consider the object classes customer and order that may exist in a typical information system and how they interact. a CUSTOMER PLACES zero or more ORDERs an ORDER IS PLACED BY one and only one CUSTOMERs

6. Copyright Irwin/McGraw-Hill 1998 6 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley System Concepts for Object Modeling  Object/Class Relationships  We graphically illustrate the association(relationship) between two classes as a connecting line.  A verb phrase describes the relationship.  All relationships are implicitly bi-directional, meaning that they can interpreted in both directions.  What is multiplicity?  Multiplicity defines the minimum and maximum number of occurrences of one object/class for a single occurrence of the related object/class.  Because all relationships are bi-directional, multiplicity must be defined in both directions for every relationship.

7. Copyright Irwin/McGraw-Hill 1998 7 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley

8. Copyright Irwin/McGraw-Hill 1998 8 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley

9. Copyright Irwin/McGraw-Hill 1998 9 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley

10. Copyright Irwin/McGraw-Hill 1998 10 Object Modeling Prepared by Kevin C. Dittman for Systems Analysis & Design Methods 4ed by J. L. Whitten & L. D. Bentley