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UMLtoDB Service: Avoiding NOT NULL constraints on columns
A quick note to answer the question of a user of the UMLtoDB Service that wonders how to avoid NOT NULL attribute constraints in SQL DDL scripts generated from UML Class diagrams.
A NOT NULL constraint on a column X is the way MOLA:UMLtoDB guarantees minimum multiplicity constraints in the attributes of UML classes. Therefore, to avoid a NOT NULL constraint on column X the only thing you need to do is to make sure that the attribute X (or association, if X is part of a foreign key) has a zero minimum multiplicity.
Some tools, like ArgoUML, use a 1-minimum multiplicity as default value for all attributes so be careful to change this default option if you prefer otherwise.
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