An Oracle database stores the objects associated with a single installation of Oracle E-Business Suite. Product code objects are stored in the APPS schema; product data objects are stored in the relevant base product schemas. Product code objects include packages, procedures, functions, triggers, views, materialized views, java classes, and queues.
What does the APPS schema do?
The APPS schema has access to the complete Oracle E-Business Suite data model. Oracle E-Business Suite responsibilities connect to an APPS schema, and the environment variable FNDNAM is set to the name of the APPS schema. The APPS schema owns all the code objects for the Oracle E-Business Suite, and has access to all data objects. There is one APPS schema for every product installation group.
Utilizing a single schema that has access to all objects avoids cross-product dependencies, and creates a hub-and-spoke access model rather than the spider web model that would otherwise be needed. The APPS schema also improves the reliability of and reduces the time needed for installation, upgrading, and patching, by eliminating the need for cross-product grants and synonyms.
It wasn't always "APPS"
Older versions of EBS were delivered with a different default schema name: APPS_FND. Some older versions even allowed you to override the default name of the schema prior to installation.
Recent versions of Oracle E-Business Suite use the APPS schema by
default. It is not possible to change the name of the APPS schema.
Hardcoded references to APPS are not permitted
We have many upgrade-related scripts, tools, and utilities. All of these standard EBS tools are required to handle any EBS schema name, regardless of whether it is named APPS, APPS_FND, or something else. There should be no hardcoded references to, say, the APPS schema. This development standard is enforced by regular automated scans of the entire EBS source code.
Earlier versions of some EBS upgrade scripts may have had hardcoded references to APPS. Running an upgrade to, say, EBS 12.2 against an EBS environment with an EBS schema named APPS_FND would fail in certain circumstances. This is not expected behavior. We would regard that as a bug that needs to be fixed immediately.
All E-Business Suite scripts with hardcoded APPS schema references have since been superceded by later versions that can handle any EBS schema names. To avoid issues with non-standard schema names, make sure that you're using the latest Rapid Install and AD/TXK utilities. Click on the "Upgrade Recommendations" link in the sidebar of this site for pointers to the latest utilities.
It is possible to integrate E-Business Suite environments with Oracle Identity Manager (OIM), which offers connectors that handle user provisioning. Those OIM connection scripts still contain hardcoded references to the APPS schema (bug 24613821).
If you encounter any issues with non-standard EBS schema names, please log a formal Service Request with Oracle Support. You are welcome to drop me a line or post a comment here, too, if your schema-related SR gets stuck in the pipeline for some reason.