How to determine Oracle 10g Home programatically?

Question

With the Oracle 9i client, I was able to figure out (in a program or install script) where the Oracle 9i home folder was by looking at the registry key /HKEY_LOCAL_MACHINE/Software/Oracle/Oracle_Home. However, I don't see anything like this for the Oracle 10g client. I see a branch entitled KEY_OraClient10g_home but I don't think that is consistant across all Oracle 10g client installs (i.e. I think I entered the name OraClient10g_home when I installed the client).
So... is there a way (programatically) to determine what the 10g home folder is? Thanks.
Tom

Answer 1

I just checked a fresh install of 10gR2, and a hybrid we have that is running 9iR2 with a 10g client in place. If you are looking for 10g home information, you will want to enumerate keynames under the HKLM/Software/Oracle key. You are looking for keys that begin with KEY_. These are likely Oracle homes.
While it is true that you can name your Oracle home what you want to, Oracle seems to prefix KEY_ to its home names the way 9i would create keys named HOMEX to describe the homes. Underneath the KEY_ key you will find the values ORACLE_HOME, ORACLE_HOME_KEY, and ORACLE_HOME_NAME that will give you all the information about the home that you might need.
While this means you have to write a loop to check for potential homes and a test to check for the value name you want to use, it should probably work. Worst case scenario is that you write a loop to iterate through the child keys under HKLM/Software/Oracle and check to see whether each key has the value ORACLE_HOME. Oracle names that value and sets its value, so you should always find it.