Read-only ViewObject and Declarative SQL mode

Introduction

The declarative SQL mode is considered to be one of the most valuable advantages of the entity-based view objects. In this mode the VO’s SQL is generated at runtime depending on the attributes showed in UI. For example, if some page contains a table with only two columns EmployeeId and FirstName, then the query will be generated as “select Employee_ID, First_Name from Employees”. This feature can significantly improve the performance of ADF application. But what about read-only or SQL-based view objects? JDeveloper doesn’t allow you to choose the SQL mode for SQL-based VOs. ?nly “Expert” mode can be used with no chance to have the query generated on the fly. But everything is possible.

In this post we have an example of some SQL-based view object VEmployees:

Let’s generate View Object Definition class:

We’re going to override some methods:

  @Override
  public boolean isRuntimeSQLGeneration()
  {
     return true;
  }

  @Override
  public boolean isFullSql()
   {
      return false;
   }

  @Override
  //In our case we know exactly the clause FROM
  public String buildDefaultFrom(AttributeDef[] attrDefs,
                                 SQLBuilder builder,
                                 BaseViewCriteriaManagerImpl vcManager)
  {
     return "Employees";
  }

  @Override
  //Setting "Selected in Query" property for each attribute except PK
  protected void createDef()
   {
     for (AttributeDef at : getAttributeDefs()) 
      if (!at.isPrimaryKey()) 
        ((AttributeDefImpl) at).setSelected(false);   
   }

Actually, that’s it! Let’s test it.

For the page showing the full set of attributes, we have the result:

And generated query (I use ODL analyzer):

For the page with only two attributes we have the following result:

And the query:

The sample application for this post requires JDeveloper 11.1.2.1.0 and standard HR schema.

Reference: Read-only ViewObject and Declarative SQL mode from our JCG partner Eugene Fedorenko at the ADF Practice blog.

Do you want to know how to develop your skillset to become a Java Rockstar?

Subscribe to our newsletter to start Rocking right now!

To get you started we give you our best selling eBooks for FREE!

1. JPA Mini Book

2. JVM Troubleshooting Guide

3. JUnit Tutorial for Unit Testing

4. Java Annotations Tutorial

5. Java Interview Questions

6. Spring Interview Questions

7. Android UI Design

and many more ....

Leave a Reply


4 − two =



Java Code Geeks and all content copyright © 2010-2015, Exelixis Media Ltd | Terms of Use | Privacy Policy | Contact
All trademarks and registered trademarks appearing on Java Code Geeks are the property of their respective owners.
Java is a trademark or registered trademark of Oracle Corporation in the United States and other countries.
Java Code Geeks is not connected to Oracle Corporation and is not sponsored by Oracle Corporation.
Do you want to know how to develop your skillset and become a ...
Java Rockstar?

Subscribe to our newsletter to start Rocking right now!

To get you started we give you our best selling eBooks for FREE!

Get ready to Rock!
To download the books, please verify your email address by following the instructions found on the email we just sent you.

THANK YOU!

Close