Is it possible to configure an Oracle DB instead of MYSQL DB for Gateway. If yes please let me know the steps.
Oracle DB is currently not supported for Gateway at this time.
Software Gateway Specifications - CA API Gateway - 9.2 - CA Technologies Documentation
Support for non-English characters: If non-English characters will be used in the Policy Manager (connected to a Software Gateway), configure the MySQL server to use "character-set-server=utf8" in the MySQL server configuration file.