Oracle JHeadstart Developer's Guide - Downloads - Oracle

A view Object key that is updateable might result in unexpected behavior in the web tier.
For example, if you update key attribute values in an ADF Faces table, the row
management feature might not work correctly anymore.
To ensure the above two conditions are met; you must perform different tasks,
depending on whether the View Object is Updateable or Read-Only.
3.3.3.1. Unchecking Reference Key Attributes for Updateable View Objects
An updateble View Object based on only one Entity Object, will inherit its key
attribute(s) from the underlying Entity Object, which in turn is inherited from the
underlying table’s primary key. Assuming you have applied common sense database
design guidelines, the primary key is not updateable, hence the View Object key is read
only as well. So far so good, however, when you start adding “Reference” Entity Objects
to the View Object, for example to join lookup data in the query, ADF Business
Components will add the key attributes of the reference Entity Object to the key of the
View Object (JDeveloper bug 6804062, fixed in 11g).
For example, we want to display the Department Manager Name on a page that lists all
departments. We need to join the Departments table with the Employees table in the
View Object query. The easiest way to do this is by adding the Employees Entity Object
as Reference Entity Object, as shown in the picture below.
Once you added the Employees Entity Object, and added some Employee attributes to
the View Object, ADF Business Component nicely changes the SQL statement for you to
join with the Employees table. However, the key attribute of the Employees Entity
Object, EmployeeId is also checked, effectively adding this attribute to the Key of a View
Object Row. So, ADF Business Components silently made your Row Key updateable.
When you subsequently use JHeadstart to generate a List of Values window to change
the manager of a department in a table layout, you will notice that the LOV values are
not returned as expected. This is because the Row Key has changed in the middle of this
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