DB Diagram: Modality Difference between NOT NULL and check constraint
705727Nov 10 2009 — edited Nov 19 2009Hi,
I am using jdev 11g (11.1.1.10) I am trying to create a db diagram from two tables. I have a FK that is NOT NULL (defined on the column). When i try to display these two tables modality, it does not show up in the diagram. I noticed that there are two ways NOT null can be defined on a table (right click on the db object to edit it; a) under column definitions there is a check box for not null, b) there is a check constraint that one can add to do not null.
I am confused and was wondering whether I must I have check constraints on the database in order to display modality (optional versus mandatory). Logically speaking it does not make any sense though.