The database interactive query function, provided by the OS/400 licensed program, supports DDM files. This support is used by Client Access, OfficeVision, and System/38-compatible query utility if OPTIMIZE(*YES) is specified. You can query remote files using the Open Query File (OPNQRYF) command, but only if the remote files are on a target AS/400 system or a target System/38. See OPNQRYF (Open Query File) Command for more information on the OPNQRYF command.
The query utility on the System/38 can be used to query remote files that are not from an AS/400 system. (See System/38-Compatible Query Utility (Query/38) for more information on the System/38-compatible query utility support.)
Database query allows accessing of either multiple local files or multiple remote files (via DDM files) at the same time, but not both. If all the files are remote, they must all reside on the same target system. Also, the DDM files that refer to the remote files must all specify the same remote location information. If this restriction is not met, an error message is displayed to the user of Client Access or to the user of the Open Query File (OPNQRYF) command who requested the query.