Specifies the size of the increment and the direction (ascending
    or descending) of the sequence. This numeric value must be in the
    range -2147483648 through 2147483647, excluding 0. The absolute
    value must be less than the difference between MAXVALUE and
    MINVALUE. A negative value specifies a descending sequence; a
    positive value specifies an ascending sequence. If the existing
    value is positive, then the new value must also be positive.
    Likewise, if the existing value is negative, then the new value
    must also be negative. That is, you cannot change a sequence from
    ascending to descending or from descending to ascending.