oracle patching
I was reading the readme for patch 19507770
It says that the following pre-requisites are required
[required]
This patch requires additional code levels to have been successfully applied to your system before it can be applied. These code levels, as at the time that this patch was built, are listed below. Please check 'My Oracle Support' to determine if any of these have been superseded R12.AD.B.delta.3 R12.ATG_PF.B.delta.3 R12.HR_PF.B.delta.6
The only method I know to find out if a particular patch is installed is by knowing the patch number
Hence I have to first find the patch number like I did below