In this example, an SMS-managed alternate index is defined. Data class is not used, and explicitly defined attributes override any attributes in the default data class.

//DEFAIX   JOB  ...
//STEP1    EXEC PGM=IDCAMS
//SYSPRINT DD   SYSOUT=A
//SYSIN    DD   *
      DEFINE ALTERNATEINDEX -
           (NAME(EXMP2.AIX) -
           RELATE(EXAMPLE.SMS2) -
           KEYS(3 0) -
           RECORDSIZE(40 50) -
           KILOBYTES(1600 200) -
           NONUNIQUEKEY -
           UPGRADE)
/*

The DEFINE ALTERNATEINDEX command creates an alternate index entry, a data entry, and an index entry to define the alternate index EXMP2.AIX. The command's parameters are:

• NAME indicates that the alternate index's name is EXMP2.AIX.
• RELATE identifies the alternate index base cluster, EXAMPLE.SMS2. Because an SMS-managed alternate index is being defined, the base cluster must also be SMS-managed.
• KEYS specifies the length and location of the alternate key field in each of the base cluster's data records. The alternate key field is the first three bytes of each data record.
• RECORDSIZE specifies that the alternate index's records are variable length, with an average size of 40 bytes and a maximum size of 50 bytes.
• KILOBYTES allocates the minimum number of tracks required to contain 1600 kilobytes for the alternate index's space. When the alternate index is extended, it is to be extended by the minimum number of tracks required to contain 200 kilobytes.
• NONUNIQUEKEY means the alternate key value might be the same for two or more data records in the base cluster.
• UPGRADE opens the alternate index by VSAM and upgrades it each time the base cluster is opened for processing.