Object Oriented Analysis -- A Historical View “Data Processing” Era: Processes Stored in Programs Data in Associated Files Payroll Payroll Data Purchasing Purchasing Data Budgeting Budgeting Data Retirement Retirement Data --Data files designed for use with particular Programs --Data shared with some difficulty since when the original program changed, the data usually changed too. --Programs and their data were “silos” not understood except by their own programmers.

Object Oriented Analysis -- A Historical View “Data Independence” Era: Processes Stored in Programs A Single Source of Data in a Shared DataBase Payroll Purchasing Budgeting Retirement --Data designed separately from programs, with eye to meeting whole organization needs. --Data easily shared between programs --Data understood by all. -- Programs could be easily changed, as long as they didn’t change the data. -- Programs could be insulated from changes to data that didn’t affect them. One Shared Database for All Processes

Object Oriented Analysis -- A Historical View “Object Oriented” Era: Objects, each with its own processes and its own data Vendor --processes --data --Each Object “knows” the things about itself that it has to. It “knows” how to do the things it has to do. -- Communication by Messages to and between Objects --Everyone knows what things each object can do, and what the message should look like to request a particular service from an object. --Data and processes are “encapsulated” protected from changes from the outside, and available only from the object itself through some message. So Object processes and data are not understood except by their own programmers. Invent.Item --processes --data Cust Order --processes --data Employee --processes --data Message

Historical Rental Date Customer Cust ID Name Mem Stat Late Fees Current Rental Date Out Due Date Check Out Movie Check In Movie Movie Movie ID Title Get Price Price Cat Price code Description M-Price N-Price Content Cat Category code Description 1.Ask for Name, Late Fees (CustID). 2.Do “Get Price” (CustID, MovieID) 3.Ask for M-Price, N-Price (PriceCode) 6.Update LateFees (CustID) 4.Ask for MemStat (CustID) 5. Ask for Title (MovieID)

Benefits of Object Oriented Analysis and Programming Reuse (?) Encapsulation Inheritance Greater programmer efficiency (?) Easier to build and modify systems (?) –Travelers Insurance “Trend” 1st -- $7M and 80 person/years 2nd -- $1.5M and 18 person/years 3rd -- $.5M and 6 person/years

Object Oriented Systems: Key Terms Classes versus Objects Attributes of a Class Inheritance Association Relationships Whole-part Relationships Method or Service (and Inheritance) Message Sending Encapsulation or information hiding Polymorphism Reuse

Class Object Data Entity Instance Relational Table Row of Table Objects Vs. Classes Specific Instance of the Category

Faculty Faculty ID Office Specialty Offer a course Method 2 Person Name Home Address Phone Change Address Change Phone Student Student ID Major Grade Point Register for Course Change Major Administrator Staff ID Title Organization Est. New Org Method 2 Classification Hierarchies and Inheritance

Class Name Attribute 1 Attribute 2 Attribute 3 Method 1 Method 2 Class Name Attribute 1 Attribute 2 Attribute 3 Method 1 Method 2 Class without Objects Class with Objects

Faculty Faculty ID Office Specialty Offer a course Method 2 Person Name Home Address Phone Change Address Change Phone Student Student ID Major Grade Point Register for Course Change Major Administrator Staff ID Title Organization Est. New Org Method 2 Class. Hierarchies and Inheritance– A Class with no Objects

Class Exercise: Draw the diagram for the Object Model for the following WCV objects. Use at least one Classification hierarchy and appropriate relationship associations. (Ignore Services for now.) Movie (MovieID, Title, PriceCat) Customer (Name, Address, Phone, CustID, MemStat, LateFees) Copy (MovieID, Copy#, #Times viewed) Employee (Name, Address, Phone, EmplID, Location, PayRate) CurrentRental (MovieID, Copy#, CustID, EmplID, Due Date) Prices (PriceCat, M-Price, N-Price)