When Oracle Fusion Applications business administrators customize the SaaS application's business object data model, they makes their pending modifications in the context of a named, private development area called a sandbox. The changes made in the sandbox are not visible to end users using the production application. Oracle APEX lets you create apps whose Oracle Cloud Apps REST Data Sources can work against the REST endpoints for the business objects undergoing active customization in the sandbox.

Administrators simply configure the appropriate sandbox name in their APEX application using the Shared Components, Component Settings, Oracle Cloud Applications (SaaS) REST Service page as described in Configuring an Oracle Cloud Applications (SaaS) REST Service. After a sandbox name is defined, App Builder uses the REST endpoints reflecting the pending version of the business objects that exists in that sandbox when creating, editing, and executing any REST Data Sources in that application.

This allows you to iteratively develop your Fusion Applications business objects customizations in parallel with an APEX application that needs to work with the customized version of their business object data. If your add new custom objects in the Fusion Apps backend, you can just define a new REST Data Source to use that custom object from the sandbox. If you add new custom attributes to an existing object, APEX will see those custom attributes in the sandbox, too. If you previously defined an APEX REST Data Source for a particular Oracle SaaS REST endpoint, you can easily update it to reflect new customizations you made in the meantime. For example, if you add additional attributes in the sandbox, you can just perform the following steps to iteratively see the new custom attributes in her APEX application as well:

1. Edit the existing REST Data Source, edit the Data Profile, and click Rediscover. APEX presents any new attributes and lets you extend the data profile to include them.

2. Edit an existing region in a page that is using this REST Data Source and choose Synchronize Columns from the context menu. This will include the new columns into the region in question. When performing a Synchronize Columns, if you have marked columns or page items in a region to be Commented Out, then they will remain commented out and only the new fields will be added as uncommented columns or page items as appropriate.

When it's time to publish the sandbox, the you just clear the sandbox name in your APEX app and it instantly begins using the now-published REST endpoint again.