Specifies that the partitioning key can be modified. The
    partitioning key is the column or list of columns specified in
    the STORE USING clause.

    If you modify a row in an UPDATABLE storage map, the row is not
    moved to a different storage area even if the new value of the
    partitioning key is not within the limits of original storage
    area. As a result, Oracle Rdb must consider all storage areas
    specified in the STORE USING clause when retrieving a row.

    If you specify the PARTITIONING clause, you must also specify the
    STORE USING clause when defining a storage map.

    If the PARTITIONING clause is not specified, UPDATABLE is the
    default.

    See the Oracle Rdb Guide to Database Design and Definition for
    more information regarding partitioning.