JDeveloper 10g and Oracle ADF Business Components Getting the Most Out of Your Data

1. JDeveloper 10g and Oracle ADF Business ComponentsGetting the Most Out of Your Data Avrom Roy-Faderman Senior Programmer November, 2005

2. Agenda • J2EE, ADF, and JDeveloper • Why Business Components? • Reading Data • Changing Data • Transactions • Demo • Q&A

3. What Is J2EE? • Java platform for multi-tier applications • Open • Scalable • Traditionally difficult to use • 3GL • Much time spent on application plumbing

4. Frameworks • Library of classes • Handle plumbing automatically • XML files provide customization • Can make Java more like a 4GL

5. ADF and MVC • Oracle ADF is a framework based on MVC architecture View and Controller (Desktop Clients) View (Web and Wireless Clients) Controller (Web and Wireless Clients) Model Business Services

6. ADF and MVC • Oracle ADF is a framework based on MVC architecture ADF Swing ADF UIX Struts + ADF Extensions ADF Data Bindings ADF Business Components

7. Agenda • J2EE, ADF, and JDeveloper • Why Business Components? • Reading Data • Changing Data • Transactions • Demo • Q&A

8. SQL Tables, rows Primary keys Foreign keys Transactions GB, TB Impedence Mismatch • Java • Classes, instances • Memory references • Object members • Shared heap • 100s of MB

9. SQL Tables, rows Primary keys Foreign keys Transactions GB, TB ADF BC Bridges the Gap • Java • Classes, instances • Memory references • Object members • Shared heap • 100s of MB

10. ADF BC Functionality • Reading data • Caching data • Writing data • Managing relationships • Managing transactions

11. What they Don’t Do • Create user interface (view) • Organize the flow of the application (controller)

12. Agenda • J2EE, ADF, and JDeveloper • Why Business Components? • Reading Data • Changing Data • Transactions • Demo • Q&A

13. Reading Data • ADF View Objects • ADF View Links

14. ADF View Objects • Retrieve data from the database • Manage caches of data • “View object definitions” contain SQL queries and act as templates for “view object instances”

15. Data Data Data Data Viewrows ADF View Objects • Each view object instance can execute the SQL query and cache the results View object instance Database SQL query Data retrieval Data Data Data Data Datarows

16. View Object Attributes • Every query column maps to a view object attribute • Those attributes are visible to the application EmployeeId LastName DepartmentId DepartmentName SELECT E.EMPLOYEE_ID, E.LAST_NAME, D.DEPARTMENT_ID, D.DEPARTMENT_NAMEFROM EMPLOYEES E, DEPARTMENTS DWHERE E.DEPARTMENT_ID = D.DEPARTMENT_ID

17. View Objects Don’t Write! • Classes to do DML are too heavyweight if not needed • Some query columns hard to map backwards CONCAT COUNT * + MAX

18. Reading Data • ADF View Objects • ADF View Links

19. ADF View Links • “View link definitions” relate a pair of view object definitions • View link definitions specify master/detail relationships between the SQL queries

20. ADF View Links • View link definitions have “Source” and “Destination” attributes • These attributes specify the master-detail relationship • Just like foreign key and primary key attributes specify a foreign key relationship

21. ADF View Links • A view link definition works like an additional WHERE clause applied to the detail Source attribute SELECT E.EMPLOYEE_ID, E.LAST_NAMEFROM EMPLOYEES E EmployeesView(Master) Destination attribute SELECT D.DEPARTMENT_ID, D.DEPARTMENT_NAME, D.MANAGER_IDFROM DEPARTMENTS D DepartmentsView(Detail) WHERE D.MANAGER_ID = :1

22. Agenda • J2EE, ADF, and JDeveloper • Why Business Components? • Reading Data • Changing Data • Transactions • Demo • Q&A

23. Changing Data • ADF Entity Objects • View and Entity Attributes

24. ADF Entity Objects • “Entity object definitions” correspond to database tables. • Entity object definitions are templates for “entity object instances,” which correspond to table rows.

25. Data Data Data Viewrows Data Data Data Entity objectinstances View Objects and Entity Objects • Instead of caching data themselves, view object instances can store data in entity object instances View object instance SQL query Database Data retrieval Data Data Data Datarows

26. Data Data Data Viewrows Data Data Data Entity objectinstances View Objects and Entity Objects • The entity object instances can write back to the database • Entity object definitions can specify validation rules View object instance Database DML Data Data Data Datarows

27. Entity Object Attributes • Every table column maps to an entity object attribute EmployeeId FirstName LastName Salary …

28. Changing Data • ADF Entity Objects • View and Entity Attributes

29. View and Entity Attributes • Every view object attribute can map to an entity attribute EmployeeId LastName DepartmentId DepartmentName EmployeeId FirstName LastName DepartmentId …

30. One View, Many Entities • One view object definition can map to multiple entity object definitions DepartmentId DepartmentName ManagerId LocationId … EmployeeId LastName DepartmentId DepartmentName EmployeeId FirstName LastName DepartmentId … EmpDeptView Departments Employees

31. One View, Many Entities • Then each view row will map to multiple entity object instances Data Data Data Data Viewrows Departments Data Data Data Data Data Data Data Data Entity objectinstances Entity objectinstances Employees

32. One Entity, Many Views • Multiple view object definitions can map to a single entity object definition DepartmentId DepartmentName LocationId LocationName DepartmentId DepartmentName ManagerId LocationId … EmployeeId LastName DepartmentId DepartmentName DeptLocView EmpDeptView

33. One Entity, Many Views • Then different view object instances can share data Data Data Data Data Data Data Data Data Viewrows Viewrows DeptLocViewinstance EmpDeptViewinstance Data Data Data Data Entity objectinstances

34. SQL-Only View Attributes • View attributes don’t need to map to entity attributes at all • Then they must be read-only • E.g.: Caclulated query columns

35. Read-Only View Objects • Have only SQL-Only attributes • Do not use entity objects at all • Read-only access to data • But Much faster!

36. Agenda • J2EE, ADF, and JDeveloper • Why Business Components? • Reading Data • Changing Data • Transactions • Demo • Q&A

37. Application Modules • Application modules package up the data and present it to the rest of the application • The application always talks to the business components through the application module

38. Application Module Instances • Each instance (user) of the application will get its own application module instance • The application module instance contains view object instances • View object instances use entity object instances to write

39. The Data Model • The view object instances in an application module instance are joined in master-detail relationships by “view link instances” • The resulting tree is called the “data model”

40. A Simple Data Model Instance ofEmployeesView SELECT E.EMPLOYEE_ID, E.LAST_NAMEFROM EMPLOYEES E SELECT D.DEPARTMENT_ID, D.DEPARTMENT_NAME, D.MANAGER_IDFROM DEPARTMENTS D Instance ofDepartmentsView WHERE D.MANAGER_ID = :current_employee_id Instance of DeptMgrLink

41. A More Complex Data Model IndependentInstance ofDepartmentsView MasterInstance ofEmployeesView DetailInstance ofDepartmentsView DetailInstance ofEmployeesView

42. Application Module Definitions • Templates for application module instances • Specify which view object and view link instances should go in the data model

43. Data Consistency • Each application module instance has its own set of view and entity caches • Two locking mode choices • “Pessimistic” locks (the default) acquired on DB rows as soon as data is changed in the cache • “Optimistic” locks acquired just before executing DML

44. Demo

45. Q & A