CICS VSAM Transparency for z/OS, Version 1.2


Identifying alternate index paths

The first step in mapping an alternate index is to identify the characteristics of the path. Use the access method services IDCAMS program to list the integrated catalog facility (ICF) cluster entry for the alternate index. The sample IDCAMS input statement that follows is an alternate index cluster that provides a path to the KSDS data set from earlier in this chapter in Figure 1.

 LISTCAT ENT(VID.VIDKSDS.AIX) ALL

In the IDCAMS output listing, look for the following fields:

 ATTRIBUTES                  
  KEYLEN-----------------3  
  RKP--------------------5  
  AXRKP-----------------35

The KEYLEN and AXRKP fields are significant. KEYLEN is the length of the field, and AXRKP is the offset of the alternate index field in the record, relative to zero. In this example, the key field is 3 bytes starting at the 36th byte.

Start of changeIf you see the attribute NONUNIQKEY, additional mapping is required. This is described in Non-unique alternate indexes.End of change

In the mapping of the VIDKSDS data set earlier in this chapter, the field starting at byte 36 for a length of 3 bytes is called VIDF0006. You need this information in the next step.

Note that when you map a data set base cluster that has alternate indexes, you must ensure that alternate index fields map to one or more complete DB2® columns.





Last updated: November 9, 2012 20:42:35