Specifies the character set for literals that are not qualified
    by a character set or national character set. If you do not
    specify a character set in this clause or in the NAMES ARE
    clause, the default is DEC_MCS. This clause overrides the
    character set for unqualified literals specified in the NAMES
    ARE clause. See the Oracle Rdb SQL Reference Manual for a list of
    the allowable character sets.