A fixed-point number that Oracle Rdb uses to replace a retrieved
    null value.

    A fixed-point number always includes a decimal point, even when
    there are no digits to the right of the decimal point.

    For example, if a field contains dollar and cent values, you
    may want to use 0.00 as the missing value to preserve the value
    context when Oracle Rdb retrieves and displays null values. In this
    particular case, if you do not allow null values and you do not
    specify a missing value, Oracle Rdb fills the retrieved field with
    zeros.

    Specify a number that does not exceed the defined field length
    and include a decimal point.