Q: If you run SQL over a DDM file, do all records get sent over the line and then selected? Or does selection occur before the records are returned?

- Kirk Lancaster

A: Although the Open Query File (OPNQRYF) command can process DDM files, SQL cannot. However, you can run SQL to remote relational databases using the Distributed Relational Database Architecture (DRDA). In that case, the SQL query is processed at the remote system and only the records that satisfy the query are returned to the local system.

- Mike Davenport