PowerPoint PresentationSlide 2Slide 3Slide 4Recursive RelationSlide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Slide 18Data Modelling:Modelling Object (Entity) classes, Attributes and relationshipsData Modelling/ Object Structure analysis and designLogical Data DesignPhysical Database designEntity, Attributes, Instances:CustomerCust NameCityZipPhone #Cust # Unique Identifier: Cust# ( Primary Key)Relationships between Object Classes/ Entities:How are instance relates to another(Business rules and Policies)Customer Sales Transactions Customer Sales Transactionsinitiates0 to manyIs initiated by1 and only 1Customer Sales TransactionCardinalityMinMaxMin = 1 Existence DependencyE/ R Model:Customer Sales TransactionMinMaxAAAAAABBBBBB1,35Each Instance of class A is associated with one and only one instance of class BRecursive RelationCourseCourse ID• Subject•CourseCourse TitleCourse CreditIs a prerequisite forHas as a pre-requisiteGeneralization/ SpecializationPersonTeacher Students•Inheritance•No Cardinality ( 1 to 1)PersonTeacher StudentsMutually ExclusiveMajorGPADeptSalarySS#NameAddressComposition Relationship (HAS - A)An object instance is composed of one or more instances of another object classSales TransactionST LineCOURSECourseIDCourse TitleCredit•Subject•Course #INSTRUCTORInstrID•Last Name•First NameSCHEDULEDCLASSSchedClassIDDay of WeekStart TimeEnd Time•CourseID•InstrID•RoomIDROOMRoomIDCapacity•Bldg•Room#N-ary Relationships- Use an AssociationSome Guidelines•Identifying Classes–each class has data it must remember–each class has at least one attribute–class has several attributes–all instances have same attribute ( & methods)•Assigning Attributes to Object classes–each attribute appears only once–assign attribute to object class that it most logically describes•Identifiers (Pks) for each class–sub-class assumes identifier of super-classCompleted Object Relationship ModelObject Relationship Model with Attributes and IdentifiersCASESalesTransactionOrder #Order DateXact. TypeSub TotalSales TaxTotalCashSaleAmt RcvdPmt TypeCredit OrderAmt ChargedApp. CodeOrder PickUpPickup #flightFlightFlt #Dep TimeDep CityArr. TimeArr CityCapacityReservationTicket #Dep DateTicket ClassTicket Condition.FareCustomerCust NameCust AddressCust NumberQ2:DeductionDed-TypeDed AmtDepartmentDept. NameTime CardPay Period EndingTC-LineDateTime-InTime-OutTS-LineHrs-WorkedGross PayTime SheetPay Period EndingEmployeeSSNEmp NameTax StatusExemptsHourly RateYTO-GrossLast UpdateTime Card will have TC-Lines for employees on vacationEach TS-Line is related to only one