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

Avrom Roy-FadermanSenior Programmer

November, 2005

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Agenda

J2EE, ADF, and JDeveloper

Why Business Components?

Reading Data Changing Data

Transactions

Demo Q&A

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What Is J2EE?

Java platform for multi-tierapplications

Open

Scalable

Traditionally difficult to use 3GL

Much time spent on applicationplumbing

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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

Business Services

View (Web and

Wireless Clients)

View and Controller

(Desktop Clients)

Model

Controller (Web and

Wireless Clients)

Oracle ADF is a frameworkbased on MVC architecture

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ADF and MVC

ADF Business Components

ADF UIXADF Swing

ADF Data Bindings

Struts +

ADF Extensions

Oracle ADF is a frameworkbased on MVC architecture

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Agenda

J2EE, ADF, and JDeveloper

Why Business Components?

Reading Data Changing Data

Transactions

Demo Q&A

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Impedence Mismatch

SQL

Tables, rows

Primary keys

Foreign keys

TransactionsGB, TB

Java

Classes, instances

Memory references

Object members

Shared heap100s of MB

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ADF BC Bridges the Gap

SQL

Tables, rows

Primary keys

Foreign keys

TransactionsGB, TB

Java

Classes, instances

Memory references

Object members

Shared heap100s 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 theapplication (controller)

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Agenda

J2EE, ADF, and JDeveloper

Why Business Components?

Reading Data Changing Data

Transactions

Demo Q&A

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Reading Data

ADF View Objects

ADF View Links

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ADF View Objects

Each view object instance canexecute the SQL query andcache the results

Database

View objectinstance

DataData

DataDataData

rows

DataData

DataDataView

rows

SQL query

Data retrieval

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View Object Attributes

Every query column maps toa view object attribute

Those attributes are visibleto the application

SELECT E.EMPLOYEE_ID,E.LAST_NAME,D.DEPARTMENT_ID,D.DEPARTMENT_NAME

FROM EMPLOYEES E, DEPARTMENTS DWHERE E.DEPARTMENT_ID = D.DEPARTMENT_ID

EmployeeId

LastName

DepartmentId

DepartmentName

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View Objects Dont Write!

Classes to do DML are tooheavyweight if not needed

Some query columns hard tomap backwards

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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 attributesspecify a foreign key relationship

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ADF View Links

A view link definition works like anadditional WHERE clause applied tothe detail

SELECT E.EMPLOYEE_ID,

E.LAST_NAMEFROM EMPLOYEES E

EmployeesView(Master)

SELECT D.DEPARTMENT_ID,D.DEPARTMENT_NAME,D.MANAGER_ID

FROM DEPARTMENTS D

DepartmentsView(Detail)

WHERE D.MANAGER_ID =:1

Source attribute

Destination attribute

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Agenda

J2EE, ADF, and JDeveloper

Why Business Components?

Reading Data Changing Data

Transactions

Demo Q&A

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Changing Data

ADF Entity Objects

View and Entity Attributes

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ADF Entity Objects

Entity object definitionscorrespond to databasetables.

Entity object definitions aretemplates for entity objectinstances, which

correspond to table rows.

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View Objects and Entity Objects

Instead of caching datathemselves, view objectinstances can store data in

entity object instances

Database

View objectinstance

DataDataDataDatarows

DataDataDataViewrows

SQL query

DataDataDataEntity objectinstances

Data retrieval

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View Objects and Entity Objects

The entity object instances canwrite back to the database

Entity object definitions can

specify validation rules

Database

View objectinstance

DataDataDataDatarows

DataDataDataViewrows

DataDataDataEntity objectinstances

DML

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Entity Object Attributes

Every table column maps toan entity object attribute

EmployeeIdFirstName

LastName

Salary

EMPLOYEE_ID FIRST_NAME LAST_NAME 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 attributecan map to an entityattribute

EmployeeId

FirstName

LastName

DepartmentId

EmployeeIdLastName

DepartmentId

DepartmentName

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One View, Many Entities

One view object definitioncan map to multiple entityobject definitions

EmployeeId

FirstName

LastName

DepartmentId

EmployeeId

LastName

DepartmentId

DepartmentName

DepartmentId

DepartmentName

ManagerId

LocationId

Employees

DepartmentsEmpDeptView

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One View, Many Entities

Then each view row willmap to multiple entityobject instances

DataDataDataDataViewrows

DataDataDataDataEntity objectinstances

DataDataDataDataEntity objectinstances

Employees

Departments

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One Entity, Many Views

Multiple view objectdefinitions can map to asingle entity object

definition

EmployeeId

LastName

DepartmentIdDepartmentName

DepartmentId

DepartmentName

ManagerId

LocationId

EmpDeptView

DepartmentId

DepartmentName

LocationId

LocationName

DeptLocView

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One Entity, Many Views

Then different view objectinstances can share data

DataDataData

DataViewrows

DataData

DataDataEntity object

instances

EmpDeptViewinstance

DataDataData

DataViewrows

DeptLocViewinstance

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SQL-Only View Attributes

View attributes dont needto map to entity attributesat all

Then they must be read-only

E.g.: Caclulated querycolumns

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Read-Only View Objects

Have only SQL-Onlyattributes

Do not use entity objects atall

Read-only access to data

But

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Agenda

J2EE, ADF, and JDeveloper

Why Business Components?

Reading Data Changing Data

Transactions

Demo Q&A

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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 inan application moduleinstance are joined in

master-detail relationshipsby view link instances

The resulting tree is called

the data model

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A More Complex Data Model

MasterInstance of

EmployeesView

DetailInstance of

DepartmentsView

DetailInstance of

EmployeesView

IndependentInstance of

DepartmentsView

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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 moduleinstance has its own set of viewand 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