I have installed python 3.7.4 (64 bit) and oracle client 12.2.0 (64 bit) in my machine which is having windows 10 operating system. 
And I connect to database via robotframework-databaselibrary=1.2.4, but its displayed error as DatabaseError: DPI-1050: Oracle Client library is at version 0.0 but version 11.2 or higher is needed
Note: I have the same setup in my local and am able to connect to database successfully but when I implement the same setup and try to execute in remote machine its throwing error
The likely issue is that you have an Oracle Client library that is too old earlier in the PATH than your 12.2 Oracle Client. If you upgrade to cx_Oracle 7.3 you should get an error message that says as much. Search all of the directories in your PATH environment variable for oci.dll and check the version of each of them. Frequently older versions of the Oracle Client library were placed in C:\Windows\System32.
'DatabaseError: DPI-1050: Oracle Client library is at version 0.0 but version 11.2 or higher is needed' error is displayed in remote machine