Oracle ADF Architecture TV - Design - Architecting for PLSQL Integration

Real World ADF Design & Architecture Principles
Architecting for PL/SQL Integration
ORACLE
PRODUCT
LOGO
15th Feb 2013 v1.0

Learning Objectives
•  At the end of this module you should be able to:
–  Understand all options for integrating PL/SQL into your ADF
applications
–  Identify problem areas with global variables and pending
transactions
–  Be able to implement best practices PL/SQL access from ADF
business services and clients
Image: imagerymajestic/ FreeDigitalPhotos.net

Program Agenda
•  Motivation for PL/SQL in Java
•  SQL Data Type - Java Mismatch
•  ADF Design Considerations for PL/SQL
•  Integrating PL/SQL in ADF Business Components
•  ADF and Database Triggers
•  Summary & Best Practices

How PL/SQL is used in existing applications
•  Core Data Access Layer (Table API)
–  Data protection layer that encapsulates mostly DML operations
–  Select (database views)
–  DML through PL/SQL packages
•  Application Business Component Layer
–  PL/SQL package for application specific data access
–  Also used to convert PL/SQL types to supported Java types
–  Uses the Table API for CRUD
•  Validation and aggregation
–  Implemented in PL/SQL procedures or functions

Motivation for PL/SQL in Java
•  Why do customers want to integrate PL/SQL into Java?
–  Language Reasons
–  Data Protection Reasons
–  Legacy Application Reasons

•  PL/SQL is "the language" of the Oracle database
•  Is highly integrated with SQL
•  Platform and operation system agnostic as it’s executed in the
database
–  Simplifies upgrade and migration of an application
•  There’s no need to write data to the middle tier to perform business
operations on them
•  Oracle customers often have a PL/SQL programming background
–  Procedural vs. Object Oriented Programming
Language Reasons

•  Integrates well with database security
–  PL/SQL participates in database role based security
•  DML operations may trigger calls to PL/SQL
•  PL/SQL APIs to database tables ensure data integrity independent
of the client used to connect to the database schema
•  Data that is not queried from the database cannot be stolen or
manipulated in transit
Data Protection Reasons

•  Oracle Forms customers used PL/SQL packages to hold business
logic as per Oracle Forms recommended best practices
•  Oracle RDBMS, Forms and Designer customers have built large
numbers of PL/SQL packages in the past
–  A project to re-develop the logic in Java is considered expensive and error-prone
•  "Never Change a Winning Team"
–  Some PL/SQL applications have gone through acceptance testing or statutory
approval processes
•  Even large PL/SQL migration projects required PL/SQL and Java to
be used in parallel
Legacy Application Reasons

10 Copyright © 2012, Oracle and/or its affiliates. All rights reserved.10 Copyright © 2012, Oracle and/or its affiliates. All rights reserved.
Should PL/SQL be used within Java EE
applications?
Please advise.
Exercise

Program Agenda

SQL Data Type – Java Mismatch
•  PL/SQL and SQL data types differ from Java types
•  SQL data types need to be mapped to Java types and vice versa
•  Java DB Connectivity (JDBC) limitations
–  No support for Record Types
–  No support for %rowtype and table of %rowtype
–  Boolean data type doesn't exist in RDBMS
•  Java uses connection pooling for better performance
–  Users share a schema and don't have a 1-1 database connect relation
–  Global package variables wont work

Program Agenda

ADF Design Considerations for PL/SQL
•  Tables are accessed by PL/SQL
packages
•  If possible
–  Consider a PL/SQL data access package
per table for ease of development and
maintenance
–  Use application specific PL/SQL packages as
an abstraction layer within the database
PL/SQL Data Access Layer
Database
PL/SQLPL/SQLPL/SQL
Create, update,
delete
Create, update,
delete
Create, update,
delete
ApplicationSpecificPL/SQL

Overall Oracle Forms, ADF Architecture Choice
Database
PL/SQLPL/SQLPL/SQL
Create, update,
delete
Create, update,
delete
Create, update,
delete
Oracle
Forms

Database
PL/SQLPL/SQLPL/SQL
Create, update,
delete
Create, update,
delete
Create, update,
delete
ADF Client
Oracle
Forms
Native Java
Access

Database
PL/SQLPL/SQLPL/SQL
Create, update,
delete
Create, update,
delete
Create, update,
delete
SOAP
Services
REST
Services
ADF Client
Oracle
Forms
Native Java
Access

Database
PL/SQLPL/SQLPL/SQL
Create, update,
delete
Create, update,
delete
Create, update,
delete
SOAP
Services
REST
Services
ADF Client
Oracle
Forms
Web Service
Layer
Native Java
Access

Database
PL/SQLPL/SQLPL/SQL
Create, update,
delete
Create, update,
delete
Create, update,
delete
SOAP
Services
REST
Services
ADF Client
Oracle
Forms
ADF BC
Web Service
Layer
Native Java
Access

Program Agenda
–  PL/SQL Table API
–  PL/SQL Read Access
–  PL/SQL Function Calls

Not to bore you with a too lengthy presentation, in the
following PL/SQL integration is explained for ADF BC
only.
Note that TopLink (EclipseLink) integration is similar
and patterns and recommendations apply
Image: Ambro/ FreeDigitalPhotos.net

PL/SQL in ADF BC
ADF BC Architecture
Application
Module
View
Object
Entity
Object
1 *
Data Model XML
Definition
View Object
Base Class
XML
Definition
Entity Object
Base Class
References References
XML
Definition
AM
Base Class
References

Program Agenda
–  PLSQL Calls from View Layer

ADF BC
•  ADF Business Components can be created based on database
views and tables for read
•  Override the entity doDML method to perform entity insert, update
and delete operations using PL/SQL
•  Optionally override the lock and findByPrimaryKey methods
•  Best Practice: Create a custom PLSQLEntityImpl class that
extends the ADF BC EntityImpl class and use it as the base
class for all PL/SQL entity classes
PL/SQL as Table API

PL/SQL as Table API (DML)
•  Implementation
–  Create ADF BC entity based on database table or view
–  Create entity Impl class
–  Override doDML to call PL/SQL procedures
•  Use when
–  You only have very few entities that require to call PL/SQL when inserting,
updating or deleting data rows
•  Consider
–  Application wide generic entity base class for common PL/SQL related boilerplate
code
No Reuse Implementation

Entity
Object
XML
Definition
Custom
EntityImpl
References
Entity Object
Base Class
Extends

View
Object
Entity
Object
1*
XML
Definition
Custom
EntityImpl
References
Entity Object
Base Class
Extends
Overrides
protected void doDML(int operation,
TransactionEvent e) {
if (operation == DML_INSERT)
callInsertProcedure(e);
else if (operation == DML_UPDATE)
callUpdateProcedure(e);
else if (operation == DML_DELETE)
callDeleteProcedure(e);
}

ADF BC FrameworkCustom
Advanced Implementation (Reuse)
Entity
Object
XML
Definition
references
PlsqlEntity
Base Class
Entity Object
Base Class
PlsqlEntityDef
Base Class
EntityDef Object
Base Class
References
extends
extends
Custom Properties
set enter

About the Sample
•  Sample is an implementation of Avrom Faderman blog entry
–  http://www.avromroyfaderman.com/2008/07/the-power-of-properties/
•  Idea is to leverage entity object and attribute custom properties to
parameterize generic framework classes
•  The EntityDefImpl class loads properties for the insert, update and delete
argument lists
–  Arguments are attributes of the entity that are configured with an index number to indicate the
argument position in the stored procedure call
•  DefImpl class reads procedure names from custom properties on the entity
•  EntityImpl class uses the infromation in the DefImpl class to invoke the PL
SQL procedure
Before Showing the Screen Shots

•  Import your ADF library that
contains the ADF BC PL/SQL
Framework Extension
•  Create entity object and view
object based on database view
or table
•  Override default ADF BC entity
and entityDef class
•  Configure custom properties on
entity object and attribute
Advanced Implementation: Reference Libraries

Advanced Implementation: Override Entity Base Classes
<Entity
xmlns="http://xmlns.oracle.com/bc4j"
Name="Departments"
…
RowClass="sample.fmwext.PlSqlEntityBaseImpl"
DefClass="sample.fmwext.PlSqlEntityBaseDefImpl">
<DesignTime>
<Attr Name="_superClass"
Value="sample.fmwext.PlSqlEntityBaseImpl"/>
<Attr Name="_defSuperClass"
Value="sample.fmwext.PlSqlEntityBaseDefImpl"/>
</DesignTime>
<Attribute
...
Departments.xml

Advanced Implementation: Custom Properties

Advanced Implementation: Custom Entity Properties

Advanced Implementation: Custom Attribute Properties

•  Use when
–  You have a lot of PL/SQL APIs to integrate in ADF
–  Declarative solution is preferred over coding solution
–  You have developers with limited or no Java knowledge
•  Consider
–  Always use application wide generic fmwk entity base class for common entity
related boilerplate code (recommended as ADF BC best practice)
–  ADF is not a runtime container for PL/SQL. Use PL/SQL by exception

Program Agenda

Secret of ADF Rockstar Programmers
"Ideally you always read data from database tables or -
views using SQL queries"

View based on PL/SQL Function
•  Implementation
–  Create view object Impl class
–  Override the ViewObjectImpl methods to read data from PL/SQL
•  create()
•  executeQueryForCollection()
•  hasNextForCollection()
•  createRowFromResultSet()
•  getQueryHitCount()
•  Consider
–  Generic view object impl class for common PL/SQL code
"No Reuse" Implementation

View
Object
XML
Definition
Custom
ViewObjectImpl
References
ViewObject
Base Class
Extends

protected void create(){
…
getViewDef().setQuery(null);
getViewDef().setSelectClause(null);
}
protected void executeQueryForCollection(){…}
protected boolean hasNextForCollection(){…}
protected ViewRowImpl createRowFromResultSet(){…}
protected long getQueryHitCount(){…}
View
Object
XML
Definition
Custom
ViewObjectImpl
References
ViewObject
Base Class
Extends

Methods Explained
•  executeQueryForCollection()
–  Executes the PL/SQL statement
–  Calls setResultSetForCollection to store SQL result set as the user data for this
View Object
•  createRowFromResultSet()
–  Called to copy row in user data to ViewRowImpl instance
–  Calls populateAttributeForRow(...) for each attribute to add to new row
–  Converts SQL Types in Result Set to ADF BC attribute types
•  getQueryHitCount()
–  Calls PL/SQL procedure determining the number of rows to fetch for a query
–  Used by ADF BC getEstimatedRowCount method
What You Need To Implement

ADF BC Framework
references
PlsqlViewObject
Base Class
View Object
Base Class
PlsqlViewDef
Base Class
ViewDef Object
Base Class
References
extends
extends
Custom Properties
set enter
Custom
View
Object
XML
Definition

PL/SQL Based Programmatic View Object
•  Implementing parent-child relationship between programmatic views
–  Create ViewLink between parent and child view
–  Map parent PK VO attribute to child FK VO attribute
–  ViewLink defines BIND_<ATTRIBUTE NAME> bind variable
–  Bind variable is passed as Object[] params argument to
executeQueryForCollection method
•  Override method in custom VO IMPL class
–  "params" is an Array of Array[2]
•  [0] name
•  [1] value
–  Read bind variable and use in programmatic view object data query
Implementing Parent – Child Relationships

How can I update PL/SQL function based
view objects?
Exercise

Program Agenda

Calling PL/SQL From ADF Faces
•  Expose Java method invoking PL/SQL on the Application Module or
View Object client interface
•  Create a method binding in PageDef file
•  Use OperationBinding to invoke method binding in binding layer
–  Method arguments passed in declaratively (binding layer) or programmatically
(Java)
Managed Bean

Repeat after me 1000 times:
Always work through the binding layer
….
Image: Ambro / FreeDigitalPhotos.net

Calling PL/SQL From ADF Faces
Architecture Diagram
Database
PL/SQL
Function
Read, or Create,
or Delete
Application
Module
Data Model
AM Impl
public void invokePlSQL()
AM Client Interface
public void invokePlSQL()
PageDef
method
binding
Managed
Bean
Button

Got it! But how do you call PL/SQL from a
task flow method activity?
Exercise

Anything to consider in regards to ADF BC
application module pooling and associated
activation / passivation cycles?
Exercise

Program Agenda

Database Updates in ADF BC
•  Entity objects are bound to database views and tables
•  Entities handle data insert, update and delete operations
•  View objects with no entity association are read-only
•  Views based on entities read data from entity cache
–  Cache holds queried and updated data objects
–  If a field should refresh upon entity row update, then this value is returned from
the update statement with no extra query required
Entities and Entity Field Refresh

Database Triggers With ADF BC
Example: Update through Database Row Level Triggers
CREATE OR REPLACE TRIGGER
EMPLOYEE_BEFORE_UPDATE
BEFORE UPDATE ON EMPLOYEES
FOR EACH ROW
when ((NEW.SALARY is not null) AND
(NEW.SALARY <> OLD.SALARY))
BEGIN
if (:NEW.SALARY > 5000) THEN
:NEW.COMMISSION_PCT := 0.25;
ELSE
:NEW.COMMISSION_PCT := 0.5;
END IF;
END;

Database Triggers With ADF BC
Example: Update through Database Row Level Triggers
BEGIN UPDATE EMPLOYEES Employees SET SALARY=:1 WHERE EMPLOYEE_ID=:2 RETURNING COMMISSION_PCT INTO :3; END;

Program Agenda

PL/SQL in ADF
•  Remember not all PL/SQL is suitable for integration
–  Many PL/SQL routines were written over 10 years ago
–  Used by many different systems interfacing into the database
–  Have been maintained by extended generation of programmers
–  Are brittle in terms of how they are used
–  Any slight change to suit new functionality required by your ADF application can have ongoing
impacts
–  Do silly things like issue database commits/rollbacks in the middle of the transactional
processing, which is undesired by ADF applications
•  PL/SQL integration should be implemented such that you can later easily
replace calls to PL/SQL with equivalent Java calls
Setting Expectations Right

PL/SQL in ADF
•  Java EE uses connection pooling
–  ADF application doesn't connect to individual database user accounts
–  Database user session is not kept between request
–  Database doesn't share ADF web session
•  Database functionality like label security need to get user context
injected with each request
•  ADF BC view object and entity caches don't synchronize with data
changes applied in database
•  A commit performed in PL/SQL is not recognized by ADF BC
•  Locking behavior of ADF BC and PL/SQL may conflict
Setting Expectations Right

PL/SQL in ADF
•  ADF is not Oracle Forms
–  Recommendations for best practices in ADF differ from those in Oracle Forms
•  Oracle Forms recommended best practice is to store business logic
in the database
–  PL/SQL is the programming language of Oracle Forms
–  Oracle Forms does not have the option to extend or reuse data blocks
•  To protect tables from direct Forms access you need to use PLSQL as a table
wrapper
•  Java EE has different ways to handle "Forms" problems
Addressing Oracle Forms Best Practices

PL/SQL in ADF
•  Using PL/SQL in Oracle ADF doesn't turn Oracle Forms into Oracle ADF
developers
–  Same for PL/SQL application developers
–  Use PL/SQL for integration and while migrating applications towards Oracle ADF
–  At the same time prepare for a Java based substitution of PL/SQL where possible
•  Allow Oracle Forms and PL/SQL application developers to learn Oracle
ADF
–  Learn Oracle ADF properly before making any decision about how to migrate
–  Forms to Oracle ADF integration is not easy and not straight forward. Don't
underestimate the effort
Addressing Oracle Forms and PLSQL Application Migration

Conclusion I/II
•  Separate PL/SQL Java logic from application logic
–  Create
•  PLSQL Java util classes
–  Wrap calls to PL/SQL by exposing methods for the most
common use cases (e.g. Stored procedures calls having up
to 3 arguments)
•  Base PL/SQL entities
•  Base PL/SQL view objects
•  Enable custom entity and view implementation classes
for configuration through properties

Conclusion II/III
•  Refactor your code up in the Java call hierarchy if it is
generic so it can be reused
•  Refactor code into helper classes if it can be used on
all layers
•  Fix PL/SQL integration problems in the database tier
–  Write PL/SQL procedures and functions as a wrapper around
existing functions
–  For example: the following database types are not supported in
JDBC and require a work around
•  Record Types
•  %rowtype and table of %rowtype

Conclusion III/III
•  ADF is not a container for PL/SQL!
–  Java is the primary language of ADF
–  Use PL/SQL only when and where needed
•  Always work through the binding layer when
accessing PL/SQL procedured and function
from a managed bean
–  Exceptions are handled by the ADF binding error handler
–  Consistent programming model

Further Reading
•  Oracle Forms developers should see:
–  When and how to migrate Oracle Forms applications
•  http://www.youtube.com/watch?v=C4Dz8zO623U
–  ODTUG article about the myths in migrating Oracle Forms
•  http://www.oracle.com/technetwork/developer-tools/forms/documentation/formsmigration-133693.pdf
–  ADF Summit: Oracle Forms to Oracle ADF redevelopment study
•  http://download.oracle.com/otn_hosted_doc/jdeveloper/11gdemos/SummitADF/
SummitADF_Redevelopment.pdf

Further Reading
•  http://www.oracle.com/technetwork/developer-tools/jdev/
documentation/index.html
–  Oracle JDeveloper and ADF Documentation Library
–  Fusion Developer Guide
•  How to Implement the Stored Procedure Calls for DML Operations
•  Avrom Faderman blog entry about maximum reuse of entities and
view objects
–  http://www.avromroyfaderman.com/2008/07/the-power-of-properties/

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