Auto Patch (adpatch) is a utility that is used to apply individual patches, mini-packs, or maintenance packs to an existing Oracle Applications instance.

Oracle Applications Patch Types

• Standalone/One off patches: Standalone patches are used to fix single or particular problems.
• Mini Packs: Mini Pack consist of Standalone patches for a particular product like AD, GL, AP and named like 11i.GL.E (Means this group of patches contain fix for 11i GL product (General Ledger till time E is released) This is commutative which means it will include 11i.GL.A, 11i.GL.B ….11iGL.D till 11i.GL.E .
• Family Pack: Family Pack patches consist of Mini Pack . They are usually named as 11i_PF. Few example of families are HR ( 11i.HR_PF.K ) _PF indicate Product Family Pack.
• Maintenance Pack: This is made up for family packs. Maintenance packs upgrade the system from one release to a higher release for example when you apply the 11.5.10.2 maintenance pack to a 11.5.9 system you upgrade your entire oracle applications to a higher version.

Patch Driver Types

The "C" drivers (copy) are file system drivers, these are used to update the file system with the new versions of certain files.

The "D" drivers are database drivers and they run SQL scripts that update database tables and objects.

The "G" drivers are also file system drivers , they generate forms and reports.

The “U” drivers content “C”,”D” and “G” drivers into single driver file called unified driver.