Specifies the character set for parameters that are not qualified
    by a character set and are not defined as a national character
    data type. 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 specified in the NAMES ARE clause.
    See the Oracle Rdb SQL Reference Manual for a list of the
    allowable character sets.