Specifies a name for a particular attach to a database.
    Specifying an alias in the connect expression lets your program
    or interactive SQL statements refer to more than one database.

    You do not have to specify an alias in the CONNECT statement if
    you are referring only to the default database.

    If you specify an alias, but do not specify a FILENAME or
    PATHNAME, SQL uses the path name or file name in the DECLARE
    ALIAS statement for that database by default. The alias must be
    part of the default environment.