Specifies the character set used for the default, identifier,
    and literal character sets for the module. Also specifies the
    character string parameters that are not qualified by a character
    set or national character set. If you do not specify a character
    set, the default is DEC_MCS.

    You must ensure that the character set specified in this clause
    matches the character set of all the databases attached to by
    any particular connection and must contain ASCII characters. See
    the Oracle Rdb SQL Reference Manual for a list of the allowable
    character sets.