jdeveloper 10g and oracle adf business components getting the most out of your data
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JDeveloper 10g and Oracle ADF Business Components Getting the Most Out of Your Data. Avrom Roy-Faderman Senior Programmer November, 2005. Agenda. J2EE, ADF, and JDeveloper Why Business Components? Reading Data Changing Data Transactions Demo Q&A. What Is J2EE?. - PowerPoint PPT PresentationTRANSCRIPT
JDeveloper 10g and Oracle ADF Business ComponentsGetting the Most Out of Your Data
Avrom Roy-FadermanSenior Programmer
November, 2005
Agenda
• J2EE, ADF, and JDeveloper• Why Business Components?• Reading Data• Changing Data• Transactions• Demo• Q&A
What Is J2EE?
• Java platform for multi-tier applications
• Open• Scalable• Traditionally difficult to use
3GL Much time spent on application
plumbing
Frameworks
• Library of classes Handle plumbing automatically XML files provide customization Can make Java more like a 4GL
ADF and MVC
Business Services
View (Web and Wireless Clients)
View and Controller (Desktop Clients)
Model
Controller (Web and Wireless Clients)
• Oracle ADF is a framework based on MVC architecture
ADF and MVC
ADF Business Components
ADF UIXADF Swing
ADF Data Bindings
Struts + ADF Extensions
• Oracle ADF is a framework based on MVC architecture
Agenda
• J2EE, ADF, and JDeveloper• Why Business Components?• Reading Data• Changing Data• Transactions• Demo• Q&A
Impedence Mismatch
•SQL•Tables, rows•Primary keys•Foreign keys•Transactions•GB, TB
•Java•Classes, instances•Memory references•Object members•Shared heap•100s of MB
ADF BC Bridges the Gap
•SQL•Tables, rows•Primary keys•Foreign keys•Transactions•GB, TB
•Java•Classes, instances•Memory references•Object members•Shared heap•100s of MB
ADF BC Functionality
• Reading data• Caching data• Writing data• Managing relationships• Managing transactions
What they Don’t Do
• Create user interface (view)• Organize the flow of the
application (controller)
Agenda
• J2EE, ADF, and JDeveloper• Why Business Components?• Reading Data• Changing Data• Transactions• Demo• Q&A
Reading Data
• ADF View Objects
• ADF View Links
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”
ADF View Objects
• Each view object instance can execute the SQL query and cache the results
Database
View object instance
View object instance
DataData
DataDataData
rows
DataData
DataDataView
rows
SQL queryData retrieval
View Object Attributes
• Every query column maps to a view object attribute
• Those attributes are visible to the application
SELECT E.EMPLOYEE_ID, E.LAST_NAME, D.DEPARTMENT_ID, D.DEPARTMENT_NAMEFROM EMPLOYEES E, DEPARTMENTS DWHERE E.DEPARTMENT_ID = D.DEPARTMENT_ID
EmployeeId
LastName
DepartmentId
DepartmentName
View Objects Don’t Write!
• Classes to do DML are too heavyweight if not needed
• Some query columns hard to map backwards
Reading Data
• ADF View Objects
• ADF View Links
ADF View Links
• “View link definitions”
relate a pair of view object
definitions
• View link definitions specify
master/detail relationships
between the SQL queries
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
ADF View Links
• A view link definition works like an additional WHERE clause applied to the detail
SELECT E.EMPLOYEE_ID, E.LAST_NAMEFROM EMPLOYEES E
EmployeesView(Master)
SELECT D.DEPARTMENT_ID, D.DEPARTMENT_NAME, D.MANAGER_IDFROM DEPARTMENTS D
DepartmentsView(Detail)
WHERE D.MANAGER_ID = :1
Source attribute
Destination attribute
Agenda
• J2EE, ADF, and JDeveloper• Why Business Components?• Reading Data• Changing Data• Transactions• Demo• Q&A
Changing Data
• ADF Entity Objects
• View and Entity Attributes
ADF Entity Objects
• “Entity object definitions” correspond to database tables.
• Entity object definitions are templates for “entity object instances,” which correspond to table rows.
View Objects and Entity Objects
• Instead of caching data themselves, view object instances can store data in entity object instances
Database
View object instance
View object instance
DataDataDataDatarows
DataDataDataViewrows
SQL query
DataDataDataEntity objectinstances
Data retrieval
View Objects and Entity Objects
• The entity object instances can write back to the database
• Entity object definitions can specify validation rules
Database
View object instance
View object instance
DataDataDataDatarows
DataDataDataViewrows
DataDataDataEntity objectinstances
DML
Entity Object Attributes
• Every table column maps to an entity object attribute
EmployeeId
FirstName
LastName
Salary
…
EMPLOYEE_ID FIRST_NAME LAST_NAME SALARY ...
Changing Data
• ADF Entity Objects
• View and Entity Attributes
View and Entity Attributes
• Every view object attribute can map to an entity attribute
EmployeeId
FirstName
LastName
DepartmentId
…
EmployeeId
LastName
DepartmentId
DepartmentName
One View, Many Entities
• One view object definition can map to multiple entity object definitions
EmployeeId
FirstName
LastName
DepartmentId
…
EmployeeId
LastName
DepartmentId
DepartmentName
DepartmentId
DepartmentName
ManagerId
LocationId
…
Employees
DepartmentsEmpDeptView
One View, Many Entities
• Then each view row will map to multiple entity object instances
DataDataDataDataViewrows
DataDataDataDataEntity objectinstances
DataDataDataDataEntity objectinstances
Employees
Departments
One Entity, Many Views
• Multiple view object definitions can map to a single entity object definition
EmployeeId
LastName
DepartmentId
DepartmentName
DepartmentId
DepartmentName
ManagerId
LocationId
…
EmpDeptView
DepartmentId
DepartmentName
LocationId
LocationName
DeptLocView
One Entity, Many Views
• Then different view object instances can share data
DataData
DataDataView
rows
DataData
DataDataEntity object
instances
EmpDeptViewinstance
DataData
DataDataView
rows
DeptLocViewinstance
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
Read-Only View Objects
• Have only SQL-Only attributes
• Do not use entity objects at all
• Read-only access to data• But
Agenda
• J2EE, ADF, and JDeveloper• Why Business Components?• Reading Data• Changing Data• Transactions• Demo• Q&A
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
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
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”
A Simple Data Model
Instance ofEmployeesViewInstance of
EmployeesView
Instance ofDepartmentsViewInstance of
DepartmentsView
Instance of DeptMgrLink
SELECT E.EMPLOYEE_ID, E.LAST_NAMEFROM EMPLOYEES E
SELECT D.DEPARTMENT_ID, D.DEPARTMENT_NAME, D.MANAGER_IDFROM DEPARTMENTS D
WHERE D.MANAGER_ID = :current_employee_id
A More Complex Data Model
MasterInstance of
EmployeesViewMaster
Instance ofEmployeesView
DetailInstance of
DepartmentsViewDetail
Instance ofDepartmentsView
DetailInstance of
EmployeesViewDetail
Instance ofEmployeesView
IndependentInstance of
DepartmentsViewIndependentInstance of
DepartmentsView
Application Module Definitions
• Templates for application
module instances
• Specify which view object
and view link instances
should go in the data model
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
Demo
Q & A