Used to specify the way NULL values for columns with a DEFAULT constraint must be handled.
property KeepNulls: boolean;
If this option is set to False, each NULL value inserted into a field with a DEFAULT constraint will be replaced with the default value. If KeepNulls is set to True, NULL values inserted into a field with a DEFAULT constraint will not be replaced with the default values. The default value of the KeepNulls property is False.