Oracle JHeadstart Developer's Guide - Downloads - Oracle

However, when the block is updateable, it is quite likely that a List of Values (LOV) has
been defined in the form that populates the foreign key item (for example
department_id), as well as lookup items (for example department_name). If such an LOV
is present, JFG will create so-called calculated attributes for the lookup items that are
populated through an LOV. The calculated attribute gets a SQL expression that returns
the lookup item value based on the Record Group Query associated with the LOV.
In addition for the VO’s created for data blocks, read-only VO’s, not based on an EO, are
created for each Record Group Query found in the form. These read-only VO’s are used
as the data collection for the LOV groups created in the JHeadstart Application
Definition.
The WHERE and ORDER BY clauses of the data blocks are also migrated to the View
Object. Any references to block items are replaced with Query Bind variables, and in the
JHeadstart Application Definition, the Query Bind Arguments group property is set up
to populate these bind variables with the correct values. References to Forms globals and
system variables cannot be replaced with bind variables, and therefore these references
are changed to literal values by enclosing them in brackets, to keep the SQL query valid.
When the JFG encounters such a reference to a Forms global or System variable, you are
notified in the log window. Make sure you revisit these View Object and change the
query, where clause or order by clause as needed.
13.4.1.4. View Links
When a relation has been defined between two data blocks in the form, the JFG attempts
to create a view link between the View Objects created for the two blocks involved.
First, the JFG tries to find a foreign key constraint between the two tables, as defined in
the data dictionary. If such a foreign key constraint exists, the view link is created based
on this foreign key. If no foreign key is found, JFG parses the content of the forms
Relation Join Condition property. If the value of this property exists of one or more
conditions connected with the AND operator and each condition uses a simple ‘=’
operator with two item references, JFG creates a view link based on the attributes created
for these items. If the Relation Join Condition is more complex, or the JFG cannot find
matching attributes for the items, the JFG will display a warning in the log window:
In such a situation, the view link will be created without source and destination
attributes. You will need to add those attributes manually by double clicking on the view
link.
13.4.1.5. Application Module
For each form, an application module is created that contains usages for all the View
Objects created for the form. Each form-specific application module is added as a nested
application module usage to the Root Application Module.
JHeadstart Developer’s Guide Forms2ADF Generator 13 - 15