AD_APPLIED_PATCHES holds information about the "distinct" Oracle Applications patches that have been applied. If 2 patches happen to have the same name but are different in content (eg. "merged" patches), then they are considered distinct and this table will therefore hold 2 records.
When populating PATCH_NAME, a name transformation is done to help tie together the comprising drivers of a patch. The transformation essentially does the following:- Removes any "D" or "DB" (or "d" or "db") appearing as a prefix or suffix in the original patch name
- Removes any "bug_" text appearing as a prefix in the original patch name
