Sometimes I get Oracle connection problems because I can\'t figure out which tnsnames.ora file my database client is using.
What\'s the best way to figure this out?
Not direct answer to your question, but I've been quite frustrated myself trying find and update all of the tnsnames files, as I had several oracle installs: Client, BI tools, OWB, etc, each of which had its own oracle home. I ended up creating a utility called TNSNamesSync that will update all of the tnsnames in all of the oracle homes. It's under the MIT license, free to use here https://github.com/artybug/TNSNamesSync/releases
The docs are here: https://github.com/artchik/TNSNamesSync/blob/master/README.md
This is for Windows only, though.