What is difference between AD_BUGS and AD_APPLIED_PATCHES ?

ADPatch 

Applying a patch updates your existing system in various ways, from adding a new
feature or product to improving system performance.

patches are applied for a number of reasons, including:

■ Fixing an existing issue

■ Adding a new feature or functionality

■ Updating to a higher maintenance level
■ Applying the latest product enhancements
■ Providing interoperability to new technology stacks
■ Determining the source of an issue
■ Applying online help

Depending on the type of patch, it may update the file system, or the database, or
both.

Applying a Patch:

Step 1 -Download the patch from metalink

It is better to check the table 'AD_BUGS' if the patch is already applied then no need to apply again.

you can check list of applied patches as follows:
  select *from ad_bugs where bug_number = 'patch_number';

select *from ad_applied_patches where APPLIED_PATCH_ID = 'patch_number';

if this query returns any row then it means this patch is already applied.

to see the difference between 'AD_BUGS' and 'AD_APPLIED_PATCHES'.

AD_BUGS: 
=========
Holds information about the various Oracle Applications bugs whose fixes have been applied (ie. patched) in the Oracle Applications installation.


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.

Step 2 -Check all Per-requisites from read me file. First apply all the patche(s) which are listed in pre-requisites (if any) and then apply the required patch and if there is/are any patch suggested in post-requisite then apply those too.

  

Step -3 Check successful patch completion condition from read me file.

(If successful patch condition already meets then no need to apply the patch.)

Step -4 Upload the patch in patch directory (i.e /appshome/patch) in zip format

Extract the patch through following

unzip <file name>

Step -5 Down the application services of concerned instance. Or do exactly what else is written in "Pre-requisite" if any.

Step -6 Run .env file of concerned instance. (Optional)

e.g (/appshome/appsuat1/UAT1/apps/apps_st/appl/APPSUA T1_erpappdev.env)

Step -7 Go to the directory of patch location  /appshome/patch (i.e cd /appshome/patch)

  

Step -8 Enter the command adadmin, following command lines will appear after adadmin.

                                                                 

Press ENTER for default value.

   
(Enter the log file name with extension .log or Press Enter for default value)

Press ENTER for default value, if you enter yes means the failure activities occurred in mail.

Press ENTER for default batchsize value.

(Press ENTER for default value)

Enter the system password usually its password is  'manager'.

Enter the SYSTEMApps  Password or Press ENTER for DEFAULT.

 Enter 5 as your choice  Change Maintenance Mode.

Enter 1 as your choice  Enable Maintenance Mode.

Enter 3 as your choice  Return to main menu.

   
Enter 6 as your choice for Exit adadmin area location.

  

Step -9 Enter the command adpacth in that patch location.

Press ENTER for default APPL_TOP value.

Enter the adpatch log file name with extension .log

Press ENTER for default value.

 Press Enter for default batch size.

 Enter the SYSTEM Password by default MANAGER.

 Enter the apps password.

 Select or enter your directory where patch is placed.

Enter the driver file name placed in patch directory with .drv extension.

* Auto patch process will start now, follow the following steps after completion of auto patch.

The Final result will come like,

AutoPatch is complete.

AutoPatch may have written informational messages to the file

/appshome/appstest/apps_st/apps/admin/TEST/log/uxxxxx.drv.lgi

Errors and warnings are listed in the log file

/appshome/appstest/apps_st/apps/admin/TEST/log/uxxxxx.drv.log

and in other log files in the same directory.

Step -10 Enter the adadmin command again to disable maintenance mode.

         

         Repeat complete Step 8 and follow the following screen

Step -11 Bounce the services of DB.

Step -12 Bring up the application services.

Step -13 Check the error in patch log file in mentioned location.