If you specify the multischema attribute for your database,
    you can store data definitions in multiple schemas within
    that database. To specify the multischema attribute, use the
    MULTISCHEMA IS ON clause in a CREATE DATABASE or ALTER DATABASE
    statement. If you want SQL behavior compliant with the ANSI/ISO
    standard, you must specify the multischema attribute.

    Databases that contain multiple schemas must organize the schemas
    within one or more catalogs. To refer to data definitions in a
    multischema database, qualify the names of data definitions with
    the schema and catalog names and, optionally, qualify with an
    alias.

    When you use an alias to qualify the name of a catalog, schema,
    or object in a multischema database:

    o  Separate subordinate names from the alias and from each other
       with a period (.)  after each name.

    o  Use double quotation marks (")  to delimit the leftmost name
       pair.

    o  Use only uppercase characters in the leftmost name pair.

    The leftmost name pair in a qualified name for a multischema
    object is a delimited identifier. In an object name, each
    qualifying name is considered one level, and names with more than
    three levels are not allowed. However, a delimited identifier is
    interpreted as a single level.