Creating a Table Creator

You can automatically generate a TableCreator using:

• TopLink Workbench during development (see "Using TopLink Workbench During Development")

• DefaultTableGenerator at run time (see "Using the Default Table Generator at Run Time")

After creating a TableCreator class, you can use its API to create and drop tables (see "Creating Tables With a Table Creator").

Using TopLink Workbench During Development

To create a TableCreator class that you can use in a Java application to recreate a database schema using the SchemaManager, use this procedure:

1. Right-click the project in the Navigator and choose Export > Table Creator Java Source from the context menu. The Table Creator dialog box appears.

   You can also select the table and choose Selected > Export > Table Creator Java Source from the menu.

2. Enter a name for the table creator class and click OK. The Save As dialog box appears.

3. Choose a location for your table creator class and click OK. TopLink Workbench exports the table creator Java class to the location you specify.

Using the Default Table Generator at Run Time

To create a TableCreator class in Java using the DefaultTableGenerator, use this procedure:

1. Create an instance of DefaultTableGenerator, passing in an instance of your TopLink project:

   DefaultTableGenerator myDefTblGen = new DefaultTableGenerator(toplinkProject);
   
   

2. Create a TableCreator instance:

   • If you want a TableCreator that can support any session, use:

     TableCreator myTblCre = myDefTblGen.generateDefaultTableCreator();
     
     

   • If you want a TableCreator customized for a specific TopLink session, use:

     TableCreator myTblCre = myDefTblGen.generateFilteredDefaultTableCreator(toplinkSession);
     
     

You can also configure TopLink to use the DefaultTableGenerator to automatically generate and execute a TableCreator at run time (see "Automatic Database Table Creation").

Using Java

This section describes how to create a TableCreator class in Java, including the following:

• Creating a TableCreator Class

• Creating a TableDefinition Class

• Adding Fields to a TableDefinition

• Defining Sybase and Microsoft SQL Server Native Sequencing

Creating a TableCreator Class

To create your own TableCreator instance, you should extend TableCreator as Example 6-1 shows:

Example 6-1 Creating a TableCreator Class

public class MyTableCreator extends oracle.toplink.tools.schemaframework.TableCreator {

    public M7TableCreator() {
        setName("MyTableCreator");
        addTableDefinition(buildADDRESSTable());
    ...
    }

    public TableDefinition buildADDRESSTable() {
        TableDefinition table = new TableDefinition();
       ...
       return table;
    }
...
}

Creating a TableDefinition Class

The TableDefinition class includes all the information required to create a new table, including the names and properties of a table and all its fields.

The TableDefinition class has the following methods:

• setName

• addField

• addPrimaryKeyField

• addIdentityField

• addForeignKeyConstraint

All table definitions must call the setName method to set the name of the table that is described by the TableDefinition.

Adding Fields to a TableDefinition

Use the addField method to add fields to the TableDefinition. To add the primary key field to the table, use the addPrimaryKeyField method rather than the addField method.

To maintain compatibility among different databases, the type parameter requires a Java class rather than a database field type. TopLink translates the Java class to the appropriate database field type at run time. For example, the String class translates to the CHAR type for dBase databases. However, if you are connecting to Sybase, the String class translates to VARCHAR. For more information, see "Schema Manager Java and Database Type Conversion".

The addField method can also be called with the fieldSize or fieldSubSize parameters for column types that require size and subsize to be specified.

Some databases require a subsize, but others do not. TopLink automatically provides the required information, as necessary.

Defining Sybase and Microsoft SQL Server Native Sequencing

Use FieldDefinition method addIdentityField to add fields representing a generated sequence number from Sybase or Microsoft SQL Server native sequencing. See "Native Sequencing With a Non-Oracle Database Platform" for detailed information on using sequencing.