1. Advanced Vision Application in 3 Tiers

2. Vb app.e xe web page? Bus Object 1 Bus Object 2 Bus Object 3 Business layer ActiveX DLL (COM DLL) Presentation LayerData Layer ActiveX DLL (COM DLL) Data Object 1 Data Object 2 Data Object 3 Three Tier Logical Model

3. Presentation Services provides the interface to the end user of the system Business Services takes care of business logic or business tasks, validation and computations. Data Services provides the capability and security required to retrieve, insert, update and delete data that is required by the business service

4. UML (Unified Modeling Language) -- a graphical language for visualizing, specifying, constructing, and documenting software systems. A class diagram shows all the classes in your application what tier each class is in the relationships between the classes. UML Class Diagram Order Method1() Method2() Property 1 Property 2 Property 3 Order Class Order Class (Expanded)

5. Sample Class Diagram

6. Designing 3 Tier Systems Most Important Guidelines Presentation layer should not contain any information or names that directly relate to the data source or data schema. should not require a reference to ADO library should not contain any business logic Business layer should contain all calculations and validation. should not query the database directly should not communicate directly with the user Data layer should not contain business logic should not communicate directly with the user

7. User ServicesBusiness ServicesData Services > frmPatient > clsPatient > clsInsurance > clsPatientData > clsInsuranceData

8. NameData TypeDescription Citystringpatient’s city FirstNamestringpatient’s first name Insurance CodeIntegerpatient’s insurance code LastNamestringpatient’s last name Patient Numberintegerpatient’s ID number Phonestringpatients’s phone Policy Numberstringpatient’s policy number Statestringpatient’s state ZipCodestringpatient’s zip code Properties clsPatient

9. NameDescriptionReturn ValueArguments Absolute PositionReturns position in recordset IntegerNone Addadds a new patient record None CancelUpdateCancels a new record None Deletedeletes a recordNone FilterFilters databooleanFieldName:string Searchvalue:string MoveFirstMoves to first record none MoveNextMoves to next record none MoveLastMoves to last record none MovePreviousmoves to previous record none Methods clsPatient

10. NameDescriptionArguments PropertyChangeNotification that a property value has changed propertyname:string Events clsPatient NameDescriptionReturn ValueArguments RecordCountreturns count of records integernone Savesaves updatesnone ShowAllRecordsremoves filtersnone Sortsorts the recordsnoneSortString:string Methods

11. clsInsurance NameData TypeDescription none Properties NameDescriptionReturn ValueArguments GetInsuranceListFills an array with the codes and names of the insurance companies None NumberOfInsuranceCompaniesReturns the number of companies in list List():Variant Methods

12. NameDescriptionArguments none Events clsInsurance

13. NameData TypeDescription Citystringpatient’s city FirstNamestringpatient’s first name Insurance CodeIntegerpatient’s insurance code LastNamestringpatient’s last name Patient Numberintegerpatient’s ID number Phonestringpatients’s phone Policy Numberstringpatient’s policy number Statestringpatient’s state ZipCodestringpatient’s zip code Properties clsPatientData

14. NameDescriptionReturn Value Arguments Absolute PositionReturns position in recordset IntegerNone Addadds a new patient recordNone CancelUpdateCancels a new recordNone FilterFilters databooleanFieldName:string MoveFirstMoves to first recordnoneSearchvalue:string MoveNextMoves to next recordnone MoveLastMoves to last recordnone MovePreviousmoves to previous recordnone RecordCountreturns count of recordsintegernone Methods clsPatientData

15. NameDescriptionArguments DataChangeNotification that data for the patient record has changed none Events clsPatientData NameDescriptionReturn Value Arguments Savesaves updatesnone ShowAllRecordsremoves filtersnone Sortsorts the recordsnoneSortString:string MoveLastMoves to last recordnone MovePreviousmoves to previous recordnone Methods

16. NameData TypeDescription InsuranceRecords RecordsetHolds Recordset of Insurance Companies Properties clsInsuranceData NameDescriptionReturn ValueArguments RecordCountReturns number of recordsIntegerNone Methods NameDescriptionArguments none Events

17. Form Load Required Tasks Create connection Create patient recordset Create insurance recordset Set Connection String Open the Connection Open Patient Recordset Open Insurance Recordset Fill Insurance Combo box Close Insurance Recordset Set Sort Order Set Form Values DisplayRecordCount

18. Form Load PresentationBusinessData AVB.mdb 1.Create clsPatient object 1.Create clsPatientData object 1.Create Conn 2.Create Patient RecordSet 3.Set Conn String 4.Open Conn 5.Open Patient Recordset 6.Move First clsPatient Class_Initialize clsPatientData Class_InitializeSet mobjPatient = New clsPatient 2.UpdateProperties 1.Properties return values of current record

19. Form Load Required Tasks Create connection - DONE Create patient recordset- DONE Create insurance recordset Set Connection String - DONE Open the Connection- DONE Open Patient Recordset - DONE Open Insurance Recordset Fill Insurance Combo box Close Insurance Recordset Set Sort Order Set Form Values DisplayRecordCount

20. Form Load PresentationBusinessData AVB.mdb 1.Create clsInsurance object 1.Create clsInsurance Data object 1.Create Conn 2.Create Insurance RecordSet 3.Set Conn String 4.Open Conn 5.Open Insurance Recordset clsInsurance Class_Initialize clsInsuranceData Class_Initialize Set mobjInsurance = New clsInsurance

21. Form Load Required Tasks Create connection - DONE Create patient recordset- DONE Create insurance recordset-DONE Set Connection String - DONE Open the Connection- DONE Open Patient Recordset - DONE Open Insurance Recordset - DONE Fill Insurance Combo box Close Insurance Recordset Set Sort Order Set Form Values DisplayRecordCount

22. Form Load PresentationBusinessData AVB.mdb 1.Call GetInsurance List Method, Pass the array Ins to hold list 1.Calls GetRows method of clsInsurance Data. InsuranceRe cords 2.Sets ByRef array equal to result of GetRows 1.Returns Insurance Recordset clsInsurance GetInsuranceList Method clsInsuranceData InsuranceRecords Property mobjInsurance. GetInsuranceList Ins 2.Fill combobox with contents of Ins Array

23. Form Load Required Tasks Create connection - DONE Create patient recordset- DONE Create insurance recordset-DONE Set Connection String - DONE Open the Connection- DONE Open Patient Recordset - DONE Open Insurance Recordset - DONE Fill Insurance Combo box - DONE Close Insurance Recordset Set Sort Order Set Form Values DisplayRecordCount

24. Form Load PresentationBusinessData AVB.mdb 1.Terminate Insurance Object 1.Set mobjInsData = Nothing 1.Close Insurance Recordset 2.Close Conn 3.Terminate Insurance Recordset 4.Terminate Connection clsInsurance Class_Terminate clsInsuranceData Class_Terminate Set mobjInsurance = Nothing

25. Form Load Required Tasks Create connection - DONE Create patient recordset- DONE Create insurance recordset-DONE Set Connection String - DONE Open the Connection- DONE Open Patient Recordset - DONE Open Insurance Recordset - DONE Fill Insurance Combo box - DONE Close Insurance Recordset- DONE Set Sort Order Set Form Values DisplayRecordCount

26. Form Load PresentationBusinessData AVB.mdb 1.Calls Sort Method of clsPatient 1.Calls Sort Method of clsPatientData 1.Selects Field Name based on string that is passed 2.Calls sort method of patient recordset 3.Raises DataChange Event clsPatient.Sort clsPatientData.SortmobjPatient.Sort "Patient Number" 1.UpdatesPrope rties 2.Raises Property Change Event mobjPatientData_ DataChange() 1.Properties return values of current record 1.Assigns Form Values mobjPatient_Property Change

27. Form Load Required Tasks Create connection - DONE Create patient recordset- DONE Create insurance recordset-DONE Set Connection String - DONE Open the Connection- DONE Open Patient Recordset - DONE Open Insurance Recordset - DONE Fill Insurance Combo box - DONE Close Insurance Recordset- DONE Set Sort Order- DONE Set Form Values- DONE DisplayRecordCount

28. Form Load PresentationBusinessData AVB.mdb 1.Calls absolute position method of mobjPatient 1.Calls clsPatientDa ta.AbsoluteP osition 1.mrsPatient. AbsoluteP osition clsPatient.AbsolutePosition clsPatientData.Absolute Position mobjPatient.Absolute Position 1.Calls RecordCount Method of mobjPatient mobjPatient.Record Count 1.Calls clsPatientData. RecordCount clsPatient.RecordCount 1.mrsPatient. RecordCount clsPatientData.RecordCount

29. Form Load Required Tasks Create connection - DONE Create patient recordset- DONE Create insurance recordset-DONE Set Connection String - DONE Open the Connection- DONE Open Patient Recordset - DONE Open Insurance Recordset - DONE Fill Insurance Combo box - DONE Close Insurance Recordset- DONE Set Sort Order- DONE Set Form Values- DONE DisplayRecordCount- DONE

30. MoveLast Required Tasks mrsPatient.MoveLast DisplayRecordCount Set Form Elements

31. MoveLast PresentationBusinessData AVB.mdb 1.Calls clsPatientDa ta.MoveLast clsPatient.MoveLast 1.mrsPatient.Move Last 2.Raise DataChange Event clsPatientData.MoveLast 1.Calls MoveLast method of mobjPatient mobjPatient.MoveLast 1.UpdatesPrope rties 2.Raises Property Change Event mobjPatientData_ DataChange() 1.Properties return values of current record 1.Assigns Form Values mobjPatient_Property Change

32. Delete Required Tasks Create Command object Set Connection String Set Command String Execute Command Requery Recordset Check to see if deleted last record Update form elements

33. Delete PresentationBusinessData AVB.mdb 1.Calls clsPatientData. Delete (passes Patient ID) clsPatient.Delete 1.Calls Delete method of mobjPatient mobjPatient.Delete 1.UpdatesPrope rties 2.Raises Property Change Event mobjPatientData_ DataChange() 1.Properties return values of current record 1.Assigns Form Values mobjPatient_Property Change 1.Creates Command 2.Sets Conn 3.Sets Command Text 4.Executes 5.Requeries 6.Raises DataChange Event clsPatientData.Delete

34. Form Unload Required Tasks Close Patient RecordSet Close Connection Set Recordset = nothing Set Connection = nothing

35. Form Unload PresentationBusinessData AVB.mdb 1.Set mobjPatientData = Nothing clsPatient Class_Terminate 1.Set mobjPatient to Nothing Set mobjPatient = Nothing 1.Close Recordset 2.Close Conn 3.Set RS = nothing 4.Set Conn = nothing clsPatientData class_Terminate