Simple Join Example

This example shows a join between three tables. A location belongs to a region which belongs to a division. Many locations can belong to a region, and many regions can belong to a division. For example; the "Boston" location belongs to the "New England" region, which in turn is under the "North America" division.

The tables are LOCATION, REGION, and DIVISION. The ddl for creating these tables is in table-definitions.sql The LOCATION table has a foreign key column, REGION_ID, that points to the REGION table. Simularily the REGION table has a foreign key column, DIVISION_ID, that points to the DIVISION table. The region and division are marked as as they are not created and deleted along with the location.

The ddl for creating the table and sequences is in table-definition.sql.
The files division.xml, region.xml, and location.xml contain the details of the tables, and the Java objects we will generate.
The shell command generate.sh invokes the Xalan parser.
It applys the template oracleObjectPersisterTemplate.xsl against the data in the xml files.
The output will be written to Division.java, Region.java, and Location.java.
Use "compile.sh" to compile the source code.
The "Test.java" class demonstrates how to use the Location object.
Use "run.sh" to run the Test class.

Here are some examples of using the objects.

You can create new divisions like this:

     Division division = new Division();         // Create a new division              
     division.setDivisionName("North America");	 // set the divisions name
     division.store();                           // Insert the division to the database
     Assume that the new division was created with a primary key of "10".

Once a division is created you can create regions under it, if you have the divisions primary key:

     Region region = new Region();          // Create a new Region
     region.setDivisionId(10);              // set the foreign key to the DIVISION table
     region.setRegionName("New England");   // 
     region.store();                        // Insert to the region table
     Assume that the new region was created with a primary key of "20".

Once a division and region are created you can create locations under them:

     Location location = new Location();            // Create a new location
     location.setRegionId(20);                      // set the foreign key to the REGION table
     location.setName("Boston");                    // 
     location.store();                              // Insert to the location table
     Assume that the new location was created with a primary key of "30".

Now to read the details of a location, and it's region and division:

     Location location = new Location(30);        // Get the existing location
     System.out.println("Location name = " + location.getName() );
     System.out.println("Region name   = " + location.getRegionName() );
     System.out.println("Division name = " + location.getDivisionName() );

You can modify a location if you have it's primary key:

     Location location = new Location(30);        // Get the existing location
     location.setName("Boston downtown");
     location.store();                              // Updates the location table

     Note: You cant modify a region's, or division's properties through the location 
           class.  The region and divisions are marked "readOnly" since they may 
           have many locations belonging to them.

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