Generating a bottom-up mapping using an existing database

This task describes how to generate a bottom-up mapping when you want to create enterprise beans from relational tables. When the workbench is connected to an existing database or database view, you can generate a bottom-up mapping to create the enterprise beans. The enterprise beans created are at either EJB 1.1, 2.0, or 2.1 specification-level. The EJB to RDB mapping tools do not support creating enterprise beans at EJB 3.0 specification-level.

Before you begin

Prerequisite tasks
  1. Connect the workbench to a database by creating a connection profile.

About this task

Steps for this task

To generate enterprise beans and map based on a bottom-up mapping approach from a database connection or view:

Procedure

  1. In the Data Source Explorer view of the Data perspective, select any of the following:
    • database
    • database connection
    • specific database tables or views associated with the database connection
    • multiple database views or connections or both
    • multiple tables or views or both
  2. Right-click and select Create EJBs from Tables (1.x-2.x).
  3. In the EJB project field, you can type a new project name. If you type a new project name a new EJB project is created automatically for you when you complete the wizard. Optionally, click the New button to launch the New EJB Project wizard if you want to set additional options for the new project. See the Creating an EJB project topic for detailed instructions on this page of the wizard. Click Next.
  4. Select the tables from the database that you want to import into your project as EJB beans, and click Next. If you selected only a database or database connection in the Data Source Explorer view, you have to specify which tables are used for the creation of EJB beans. If you selected specific tables or views or both, then the check boxes for those tables is already marked.
    • In order to avoid broken foreign keys, the wizard imports any required tables.
    • If you plan on using a bean to update a view, make sure that the view supports updates. The wizard does not check whether a view can be updated.
  5. If you are working with an EJB 1.x project, under the CMP Version drop-down list, the EJB specification-level for generating the enterprise beans defaults to 1.x. If you are working with an EJB 2.x project, you have the option to select one of the following under the CMP Version drop-down list to specify the EJB specification-level for the generated enterprise beans:
    • 1.x
    • 2.x
    Note: For EJB 2.x enterprise beans, the bottom-up mapping only generates local interfaces because typically entity beans only contain local interfaces.
  6. In the Package for generated EJB classes field, type the package name for the generated enterprise bean classes.
  7. Optional: In the Prefix for generated EJB classes field, you can add a prefix name that gets added to the unique names generated by the mapping tool to avoid collision of new table mappings to existing CMP entity beans.
  8. If you selected to import and map a view, you can choose whether you want to create additional beans for the tables in the view. By default, the Do not generate beans for tables included in views check box is selected, and the wizard does not create these beans.
    Tip: When you do a bottom-up mapping, by default the wizard does not generate beans for underlying tables for views. However, because relationships need to be created for foreign keys, the wizard automatically creates a bean for any table that has any foreign keys or whose primary key is pointed to by any foreign keys from other tables. If you clear the Do not generate beans for tables included in views check box, the wizard generates beans for all tables and views in the database schema.
  9. Click Finish to generate the enterprise beans and the bottom-up mapping based on the database views that you selected in the wizard.
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