This task describes how to generate for your first time a bottom-up
mapping. Bottom-up approach assumes that the database tables already exist,
and that once the selected tables are imported, the enterprise beans and
mappings between them are automatically generated. By default, relationships
are generated where foreign-keys exist.
Prerequisite tasks- Enable the J2EE and Database Capabilities. You can complete
this as follows:
- In the workbench preferences page (Window > Preferences)
expand the folder Workbench , select Capabilites.
- Under the Capabilities list, select the Enterprise
Java check box underAdvanced J2EE. Click OK.
Steps for this taskTo generate enterprise beans and map
based on a bottom-up mapping approach:
- In the workspace toolbar, select File > New > Other.
Expand the EJB folder, and select Enterprise
Beans from Tables. Click Next.
- Complete the Database Connection page and click Next.
See Creating JDBC connections for detailed instructions on
this page of the wizard. If you have already completed this step once, you
can select the Use existing connection check box and
select an existing connection from the drop-down list.
- In the EJB project combination box, you
can type a new project name or select an existing enterprise application
project from the drop-down list. If you type a new project name, a new EJB
project will be created automatically for you when you click the Next button.
Optionally, click the New... button to launch the
New EJB Project wizard if you wish to set additional options
for the new project. See Creating an EJB project for detailed instructions on
this page of the wizard.
- Select the tables and views from the database that you want to
import, and click Next.
- 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.
- 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:
Note: For EJB 2.x enterprise beans, the bottom-up mapping only generates
local interfaces because it is normally considered best practice for entity
beans to only contain local interfaces.
- In the Package for generated EJB classes field,
type the package name for the generated EJB classes.
- 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.
- If you selected to import and map a view, you can choose whether
or not 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 will 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 schemata.
- Click Finish to generate the enterprise
beans and the bottom-up mapping based on the database tables and views that
you selected in the wizard.