1. A method comprising: receiving a first database command at a database proxy system, the first database command to operate with a first database management system, the first database command comprising language that is specific to the first database management system, the first database command not supported by a second database management system; identifying, by the database proxy system, the language in the first database command specific to the first database management system by comparing fragments of the first database command with a plurality of pattern datasets corresponding to a plurality of database management systems to match a pattern dataset specific to the second database management system; rewriting, by the database proxy system, the first database command to one or more second database commands supported by the second database management system using a rule associated with rewriting the identified language to modified language in the one or more second database commands to improve computational efficiency related to non-standard schema creation language for specific types of commands comprising outer joins; forwarding, by the database proxy system, the one or more second database commands to the second database management system.