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Determines whether empty fields are assigned a NULL value, or when applicable, filled with spaces, zero or "false".
When the rowset's autoNullFields property is set to true (the default setting), dBASE Plus allows an empty field to assume a “null value”. Null values are those which are nonexistent or undefined. Null is the absence of a value and, therefore, different from a blank or zero value.
When the rowset's autoNullFields property is set to false, numeric fields (long, float, etc.) are assigned a value of zero, logical fields a value of "false", and character fields are filled with spaces.
A null value in a field may simply indicate data has yet to be entered, as in a new row, or the field has been purposely left empty . In certain summary operations, null fields are ignored. For example, if you are averaging a numeric field, rows with a null value in the field would not affect the result as they would if the field were filled with zero, or any other value.