A storage map definition for the index. You can specify a store
    clause for indexes in a multifile database only. The STORE clause
    in a CREATE INDEX statement allows you to specify which storage
    area files are used to store the index entries:

    o  All index entries can be associated with a single storage
       area.

    o  Index entries can be systematically distributed, or
       partitioned, among several storage areas by specifying upper
       limits on the values for a key in a particular storage area.

    If you omit the storage map definition, the default is to store
    all the entries for an index in the main default storage area.

    You should define a storage area for an index that matches the
    storage map for the table with which it is associated.

    In particular, under the following conditions, the database
    system stores the index entry for a row on or near the same data
    page that contains the actual row:

    o  The storage areas for a table have a mixed page format.

    o  You specify an identical store clause for the index as exists
       in the storage map for the table.

    o  The storage map for the table also names the index in the
       PLACEMENT VIA INDEX clause.

    Such coincidental clustering of indexes and rows can reduce I/O
    operations. With hashed indexes and coincidental clustering, the
    database system can retrieve rows for exact-match queries in one
    I/O operation.

    For sorted indexes, specifying an identical storage map reduces
    I/O contention on index nodes.