Previous topic |
Next topic |
Contents |
Contact z/OS |
Library |
PDF
IDALKADD—RLS record locking z/OS DFSMS Macro Instructions for Data Sets SC23-6852-02 |
||||
The IDALKADD macro is an RLS only VSAM request macro. It is used by applications or application support packages such as CICS® File Control that perform logging of changes to VSAM data sets. With logging, it is necessary to create a log entry before making the corresponding change to the data set or database. The log entry must uniquely identify the inserted, deleted, or changed record. Logging an ADD to a KSDS in the case where VSAM rejects the ADD due to a duplicate key condition presents a problem. Also, the record identification for an ESDS is the record RBA and logging an ADD to an ESDS implies the RBA of the record is known before actually ADDing the record. This IDALKADD request addresses these two situations. IDALKADD to a KSDS, RRDS or VRRDS via the base or a path performs duplicate key or RRN checking. If a record with the specified key/RRN already exists in the base, the IDALKADD fails with the duplicate key/RRN error status. The PUT request must use the same RPL as was used by the IDALKADD. The IDALKADD and PUT NUP are a request pair in the same sense as GET UPD and PUT UPD are a request pair. Reuse of the RPL before issuing the PUT NUP cancels the IDALKADD. The length of the record specified on IDALKADD and the subsequent PUT must be the same or the PUT request is rejected with an invalid record length reason code. For a KSDS, RRDS, or VRRDS, the PUT must specify a record with the same base key/RRN as was specified by the IDALKADD request. Even though an IDALKADD is successful, the corresponding PUT NUP may fail. An example of where the PUT NUP would fail is the condition where the PUT NUP would create a duplicate key in an alternate index and the alternate index requires unique keys. In this case, the PUT NUP fails. IDALKADD is supported for both base and path access. IDALKADD is supported for both recoverable spheres and non-recoverable spheres. It is supported for KSDSs, ESDSs, RRDSs, and VRRDSs. The record lock acquired by an IDALKADD request is released as
follows:
VSAM does not support PUT NUP,SEQ in backward processing mode. This also means IDALKADD SEQ,BWD is not supported. The format of the IDALKADD macro is:
The following RPL parameters apply to this request:
|
Copyright IBM Corporation 1990, 2014
|