File Management - IBM

The library containing the to-file
WRKOBJLCK
WRKRCDLCK
If you want to display any information about a to-file, you must anticipate the
requirement and force the copy command to use block record-at-a-time operations
by specifying ERRLVL(1).
If you anticipate that problems may arise because of this, you can preallocate the
files and members using the Allocate Object (ALCOBJ) command. (See the CL
Programming book for information about preallocating objects.)
Preventing copy errors that result from constraint
relationships
A constraint relationship is a mechanism to ensure data integrity between a
dependent file and a parent file. A constraint relationship exists between a
dependent file and a parent file when every non-null foreign key value in the
foreign key access path of the dependent file matches a parent key value in the
parent key access path of the parent file. A physical data file may be a parent or
dependent file. However, a source physical file may not be a parent or a dependent
file.
The copy commands listed below allow the following relationships:
v CPYF - from-file or to-file could be a parent or dependent file
v CPYFRMQRYF - to-file could be a parent or dependent file
v CPYFRMTAP - to-file could be a parent or dependent file
v CPYTOTAP - from-file could be a parent or dependent file
v CPYFRMDKT - to-file could be a parent or dependent file
v CPYTODKT - from-file could be a parent or dependent file
See the following topics for more information about constraint relationships and
copying files:
v “Copying files not in check-pending status”
v “Copying files in check pending status” on page 128
Copying files not in check-pending status
If the parent or dependent file has an established constraint relationship that is not
in check-pending status, the following rules apply:
v If the from-file has an established constraint relationship, then you can copy all
of the records from it whether it is a parent or dependent file.
v If the to-file has an established or enabled constraint relationship, then the
following rules apply to keep the constraint relationship from entering
check-pending status:
– A parent file cannot have its member cleared of records.
– A parent file cannot have more than one parent key value in the parent key
access path of the same value (key must remain unique). That is, if the to-file
is a parent file in a constraint relationship, then the copy does not allow
duplicate key records to be copied into it.
Chapter 4. Copying files 127