File Management - IBM

For the first CPYF command, MBROPT(*ADD) is specified, so an escape message
is not sent to the program because of the empty from-file member. Note that if
MBR1 does not exist before the copy, it is added to the to-file (if either the from-file
member is empty or contains data).
For the second CPYF command, copy does not clear the to-file member when the
from-file member is empty, so the MONMSG command after the second CPYF
command starts the CLRPFM command to clear the to-file member when the
from-file member is empty.
For the third CPYF command, the CPF2817 escape message has compare data of
CPF2870 if all members to be copied are empty because the generic from-file
member name, EMPTY*, requests that multiple members be copied.
Creating a duplicate to-file member
When your application requires an exact duplicate of the records in the to-file
member (if either the from-file is empty or contains data), an alternative solution is
to use the Clear Physical File Member (CLRPFM) command:
CLRPFM FILE(X) MBR(XYZ)
CPYF FROMFILE(Y) TOFILE(X) TOMBR(XYZ) +
MBROPT(*ADD)
Because MBROPT(*ADD) is specified, the CPYF command completes normally
even if there is no data in file Y. MBR(XYZ) in file X contains an exact duplicate of
the records in the member in file Y.
CPYFRMQRYF command support for CCSIDs
The Copy from Query File (CPYFRMQRYF) command provides CCSID conversions
for character and DBCS fields. The Open Query File (OPNQRYF) command
converts all character and DBCS fields to the current job CCSID, except for fields
that have a CCSID of 65535 or where *HEX is specified on the MAPFLD
parameter. If the current job CCSID is 65535, then no conversions are done by
OPNQRYF. The CPYFRMQRYF command may also do conversions to the to-file
field CCSIDs, so it is possible that double conversions will be done and data may
be lost. To avoid the possibility of doing double conversions, change the job CCSID
to 65535 before doing an OPNQRYF if you plan to do a CPYFRMQRYF.
CPYFRMQRYF uses a different query format. It is the same as the open query file
format except for the CCSIDs for character and DBCS fields. The CCSIDs in this
query format are determined according to the following:
v If the OPNQRYF job CCSID is 65535, all character and DBCS fields in the query
format have the same CCSIDs as the open query file format.
v If the OPNQRYF job CCSID is not 65535, all character and DBCS fields in the
query format have their CCSIDs reset to the associated single-byte, mixed or
double-byte CCSIDs of the OPNQRYF job CCSID, based on the field type. Fields
with a CCSID of 65535 remain unchanged. If there is no associated mixed or
double-byte CCSID for the OPNQRYF job CCSID, 65535 is used.
You can find more information on CCSIDs in the National Language Support book.
Chapter 4. Copying files 81