identifying applied patches

Hi All,

What is the best way to figure out that the pre-request patch is already applied so we ca ignore, or it should be applied?

e.g.

I have requested to apply patch Patch 16090199:R12.ZX. I used the following query to identify the prequests:

select bug_number from ad_bugs

where bug_number IN ('8877828','9436262','10296081','13328788','13732606',

'9174978',

'12909730',

'12407622'

);

The result was as the following:

13328788

12909730

9174978

9436262

10296081

8877828