SetNullValue - method of the PmaDatabase object

It is used for setting the value that will be returned by the ReadFieldValue method if the database table cell contains the Null value.

Boolean SetNullValue(Variant vValue, Long nType)

vValue	(Variant) The value that has to be returned by the ReadFieldValue method if the Null value is returned by this property
nType	(Long) Specifies columns, the compensatory values are valid for: 1 - for integer numbers columns (of the Integer, Byte and Long type) 2 - for columns of the Boolean type 3 - for columns of the Text type 4 - for columns of the Date type 5 - for real numbers columns (of the Single, Double type)