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This normally occurs when the loading process retrieves a record during the
sequential copying of the source data set. However, it can also occur when an
application retrieves a record that is not in the data table and:
v For a user-maintained data table, loading is still in progress, or
v For a CICS-maintained data table, loading terminated before the end of the
source data set was reached (because, for example, the data table was full).
Note: For a coupling facility data table the XDTRD exit is invoked only for a table
that is loaded from a source data set.
The record retrieved from the source data set is passed as a parameter to the user
exit program—see fields UEPDTRA and UEPDTRL. Your exit program can choose
(depending, for example, on the key value—see fields UEPDTKA and UEPDTKL)
whether to include the record in the data table or not.
Alternatively, the exit program can request that all subsequent records up to a
specified key are skipped—see field UEPDTSKA; these records are not passed to
the exit program. This facility is available only during loading. You can specify the
key as a complete key, or you can specify just the leading characters by padding
the skip-key area with binary zeros.
For a user-maintained data table, the program can also modify the data in the
record to reduce the storage needed for the data table. Application programs that
use the data table must be aware of any changes made to the record format by the
exit program. If the record length is changed, the exit program must set the new
length in the parameter list—see field UEPDTRL. The new length must not exceed
the data buffer length—see field UEPDTRBL.
When invoked
Just before CICS tries to add to the data table a record that has been
retrieved from the source data set.
Exit-specific parameters
UEPDTPL
Address of the data table user exit parameter list, which is mapped
by DSECT DT_UE_PLIST in copybook DFHXDTDS. The data table
user exit parameter list contains:
UEPDTNAM
The 8-character data table name.
UEPDTFLG
A 1-byte flag field. The possible bit settings are:
UEPDTSDT (X'80')
The exit has been invoked by CICS shared data
table support.
UEPDTCMT (X'40')
This is a CICS-maintained table. Only meaningful if
UEPDTSDT is on.
UEPDTOPT (X'20')
The exit has been invoked for table loading. This
means that optimization by skipping can be
requested.
data tables program exits
34
CICS TS for OS/390: CICS Customization Guide
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