Not really. A null value in a certain column does not indicate that the field is optional; instead, the table definition having a nullable column indicates that

Not really. A null value in a certain column does not indicate that the field is optional; instead, the table definition having a nullable column indicates that the field is optional. A null value in a nullable column indicates only that the value is unknown, nothing else. This is database modeling 101: A table ("relation") describes one entity. The attributes of the entity are reflected in the table column set, and each table row represents a different instance of said entity. Marking a column as nullable means that not knowing that attribute is a recoverable situation (for example, because it is only stored for informational purposes and not for processing). If you're using the same table to store multiple entities, using nullable columns to indicate if a row represents entity A or entity B, you're doing it wrong.