Generic Catalog Selection for DELETE and LISTCAT

The multilevel alias facility enhances generic catalog selection. If you use generic catalog selection with multilevel aliases, you can select several catalogs if the number of qualification levels of the generic name is less than the maximum your system allows. See z/OS DFSMS Managing Catalogs for information about setting multilevel alias levels in the catalog address space. If the number of qualification levels in the data set name is less than the maximum your system allows, and aliases exist that match the generic data set name, then every catalog related to those aliases (including the master catalog) is selected.

The multilevel alias facility and the system-generated name format require special attention, such as:

During the DEFINE of a VSAM data set, if the specified data/index name does not point to the same catalog as the cluster, an error occurs.
During the DEFINE of a VSAM cluster or a GDG, if the name of the cluster or GDG matches an existing alias or user catalog, the DEFINE request is denied with a duplicate-name error. This is to prevent the data/index component or a GDS from becoming inaccessible.
When you add an alias to the catalog, make sure that it does not cause existing data sets to become inaccessible.

With the multilevel alias facility, a non-VSAM data set with the same high-level qualifier as an existing alias of a user catalog can be defined. For more details, see z/OS DFSMS Managing Catalogs.

The selection order is based upon alias names encountered that match the generic data set name, not upon the catalogs or the data set names selected. For LISTCAT, therefore, entries appear in the data set within alias entry order.

Should two or more aliases relate to the same catalog, only the first catalog reference is used.

If no catalogs are found in the prior searches, the master catalog is searched.

Examples:

Given that,

Alias A: is related to ICFUCAT1,
Alias A.B: is related to ICFUCAT2,
Alias A.C: is related to ICFUCAT3,
Alias A.C.D: is related to ICFUCAT4,
Alias B: is related to SYSCATLG.V338001 and,

ICFMAST is the master catalog for the system,

LISTCAT ENTRY(A.*) selects:
- ICFUCAT1
- ICFUCAT2
- ICFUCAT3
- ICFMAST
Because the master catalog is selected, the alias entries appear in the listing.
LISTCAT ENTRY(B.*) selects:
- SYSCATLG.V338001

The master catalog is not searched.