3. Installation › 3.5 Generate a Database Unit › 3.5.1 Define Catalog Indexes for Prefix and Tapeprefix

3.5.1 Define Catalog Indexes for Prefix and Tapeprefix

A database unit requires two data set name prefixes, a DASD
prefix (prefix) and a tape prefix (tapeprefix), which are
defined in 'prefix.MICS.PARMS(JCLDEF)', described in section
2.3.3.2.1, "JCL Option Definition (JCLDEF)".  These data set
name prefixes serve several purposes:

1.  They are used to give unique names to the data sets
    associated with a specific database unit.

2.  The high level qualifier of the prefixes may serve as a
    catalog index for the data sets.  This index may provide
    a pointer to either an OS CVOL or a VSAM user catalog.

3.  The prefixes provide meaningful qualification for
    identification and control of the CA MICS shared data
    sets.

The prefix and tapeprefix for a database unit must be
different from the sharedprefix and from the prefixes and
tapeprefixes for all other database units in the database
complex.  However, the prefix and tapeprefix for a unit may
be the same.  Also, the sharedprefix and the other prefixes
may have a common high level index.

Unless standards at your site prevent it, this step should be
used to ensure that the indexes established for the
tapeprefix and prefix point to a catalog other than the
master catalog.  We strongly recommend that the master
catalog not be used for cataloging CA MICS data sets,
especially in sites where there may be more than one OS/390
system on which CA MICS may be used.

In selecting a high level index for CA MICS data sets, be
aware of the following:

1.  Most sites have data set naming standards for production
    data sets.  CA MICS should be considered as a production
    system, and the high level index chosen accordingly.

2.  If a high level index of a TSO userid is selected, ensure
    that your site does not delete data sets that remain
    unreferenced over long periods of time.  For example, the
    YEARS timespan database will not be referenced for
    output until the MONTHLY job is run--once a month.

If the high level index of the prefix is a TSO userid or an
index that already exists, then the required catalog indexes
and master catalog pointers are already built and no further
action is required in this step.  If this is not the case,
then the following steps must be performed.

The choice of Access Method Services (AMS) commands used to
define this high level index depends on whether an OS CVOL or
VSAM catalog is used, and if VSAM, whether a master or user
catalog is to be used.

        AMS commands for an OS CVOL index definition (assumes
        CVOL already exists):

            DEFINE ALIAS(NAME('---name---')  -
                 RELATE('SYSCTLG.Vxxxxxx'))

        AMS commands for a VSAM Master Catalog index
        definition:

            No action required, but not recommended.

        AMS commands for a VSAM User Catalog index definition
        (assumes user catalog already exists):

            DEFINE ALIAS(NAME('---name---')  -
                 RELATE('user-catalog-name'))


The xxxxxx field in the OS CVOL example is the name of the
volume on which the OS CVOL resides.  The '---name---' field
must be the high level index of the prefix.  This index may
be common to all of sharedprefix, prefix(es) and
tapeprefix(es).

Special Considerations:

1. No action is required if the high level index has been
   defined already in the master catalog.

2. In a multi-CPU environment, it is essential that the high
   level index be defined in an OS CVOL or VSAM user catalog
   and not allowed to default to the master catalog.  Data
   sets that are cataloged in the master catalog of one
   system will not be available from any other system's
   master catalog unless the data sets are explicitly
   cataloged on that system.  The DEFINE ALIAS command should
   be executed against every system's master catalog where
   you wish to have access to CA MICS data sets.

For example, if the prefix was DB2.PRE and the tapeprefix was
DB2T.PRE, the following definitions might be made:

If an OS CVOL catalog residing on volume TSO999 was to be
used:

            DEFINE ALIAS(NAME('DB2')  -
                 REL('SYSCTLG.VTSO999'))
            DEFINE ALIAS(NAME('DB2T')  -
                 REL('SYSCTLG.VTSO999'))

    If a VSAM Master Catalog index was to be used:

            No action required, but not recommended.

    If a VSAM User Catalog named SYS.USERCAT was to be used:

            DEFINE ALIAS(NAME('DB2')  -
                 REL('SYS.USERCAT'))
            DEFINE ALIAS(NAME('DB2T')  -
                 REL('SYS.USERCAT'))