Solution for ORA-12154 TNS failing to resolve specified connection identifiers when PLSQL developer connects to the database when one machine has multiple Oracle versions installed

When using PLSQL developer, the ORA-12154:
TNS: Unable to parse the specified connection identifier "a solution to the problem plsqldeveloper version 7.1 today suddenly needs to change a project a long time ago, that project uses Oracle9i
Start PLSQL developer, prompt to enter the user name and password and database, enter, press enter, prompt: ORA-12154:
TNS: the specified connection identifier cannot be resolved. Start the net configuration assistant of Oracle9i from the Start Menu, reconfigure the local net service, and test that the local database can be connected. But in PLSQL developer, the database cannot be connected.
I also checked it from the Internet and found a wide variety of solutions. If PLSQL developer is re-installed, it still cannot be connected. After studying for a while, I wasted several minutes.
When I accidentally checked some options of PLSQL developer, I suddenly found that there was an oracle home setting. After the settings were set, the connection was normal.
It turns out that I have installed the complete Oracle9i server on my machine, and also installed an Oracle10g client, which is equivalent to having two Oracle home on my machine at the same time. During the connection, PLSQL developer uses 10 Gb home by default.
Therefore, the connection fails. In PLSQL developer, modify the Oracle home setting method: a prompt is displayed, indicating that the user name and password are correct. In this way, go to the PLSQL developer main interface, choose tools-preferences, and select Oracle-connection in the setting window, in the corresponding settings window, find Oracle
Home, select orahome92, save the settings, and restart PLSQL developer. Then you can log on normally. Of course, if you need to re-use the local net service of a 10 Gb database, you need to re-Change it back to oraclient10g_home.
You may need to record the error and try to help the person you see.