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

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

• Avrom Roy-Faderman
• Senior Programmer
• November, 2005

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Agenda

• J2EE, ADF, and JDeveloper
• Why Business Components?
• Reading Data
• Changing Data
• Transactions
• Demo
• QA

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What Is J2EE?

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

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Frameworks

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

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ADF and MVC

• Oracle ADF is a framework based on MVC
  architecture

View (Web and Wireless Clients)
View and Controller (Desktop Clients)
Controller (Web and Wireless Clients)
Model
Business Services
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ADF and MVC

• Oracle ADF is a framework based on MVC
  architecture

ADF UIX
ADF Swing
Struts ADF Extensions
ADF Data Bindings
ADF Business Components
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Agenda

• J2EE, ADF, and JDeveloper
• Why Business Components?
• Reading Data
• Changing Data
• Transactions
• Demo
• QA

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Impedence Mismatch

• SQL
• Tables, rows
• Primary keys
• Foreign keys
• Transactions
• GB, TB

• Java
• Classes, instances
• Memory references
• Object members
• Shared heap
• 100s of MB

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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

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ADF BC Functionality

• Reading data
• Caching data
• Writing data
• Managing relationships
• Managing transactions

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What they Dont Do

• Create user interface (view)
• Organize the flow of the application (controller)

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Agenda

• J2EE, ADF, and JDeveloper
• Why Business Components?
• Reading Data
• Changing Data
• Transactions
• Demo
• QA

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Reading Data

• ADF View Objects
• ADF View Links

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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

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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
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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
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View Objects Dont Write!

• Classes to do DML are too heavyweight if not
  needed
• Some query columns hard to map backwards

CONCAT
COUNT


MAX
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Reading Data

• ADF View Objects
• ADF View Links

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ADF View Links

• View link definitions relate a pair of view
  object definitions
• View link definitions specify master/detail
  relationships between the SQL queries

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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

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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
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Agenda

• J2EE, ADF, and JDeveloper
• Why Business Components?
• Reading Data
• Changing Data
• Transactions
• Demo
• QA

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Changing Data

• ADF Entity Objects
• View and Entity Attributes

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ADF Entity Objects

• Entity object definitions correspond to
  database tables.
• Entity object definitions are templates for
  entity object instances, which correspond to
  table rows.

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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
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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
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Entity Object Attributes

• Every table column maps to an entity object
  attribute

EMPLOYEE_ID FIRST_NAME LAST_NAME SALARY ...




EmployeeId FirstName LastName Salary
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Changing Data

• ADF Entity Objects
• View and Entity Attributes

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View and Entity Attributes

• Every view object attribute can map to an entity
  attribute

EmployeeId LastName DepartmentId DepartmentName
EmployeeId FirstName LastName DepartmentId
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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
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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
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One Entity, Many Views

• Multiple view object definitions can map to a
  single entity object definition

DepartmentId DepartmentName LocationId LocationNam
e
DepartmentId DepartmentName ManagerId LocationId
EmployeeId LastName DepartmentId DepartmentName
DeptLocView
EmpDeptView
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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
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SQL-Only View Attributes

• View attributes dont need to map to entity
  attributes at all
• Then they must be read-only
• E.g. Caclulated query columns

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Read-Only View Objects

• Have only SQL-Only attributes
• Do not use entity objects at all
• Read-only access to data
• But

Much faster!
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Agenda

• J2EE, ADF, and JDeveloper
• Why Business Components?
• Reading Data
• Changing Data
• Transactions
• Demo
• QA

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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

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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

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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

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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
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A More Complex Data Model
IndependentInstance ofDepartmentsView
MasterInstance ofEmployeesView
DetailInstance ofDepartmentsView
DetailInstance ofEmployeesView
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Application Module Definitions

• Templates for application module instances
• Specify which view object and view link instances
  should go in the data model

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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

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Demo
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Q A