Oracle Environment Variables
    To use DBD::ORACLE to connect to an Oracle database, ORACLE_HOME
    environment variable should be set correctly. In general, the value used
    should match the version of Oracle that was used to build DBD::Oracle.
    If using dynamic linking then ORACLE_HOME should match the version of
    Oracle that will be used to load in the Oracle client libraries (via
    LD_LIBRARY_PATH, ldconfig, or similar on Unix).