has anyone come accross a specific type of erd that uses dots to represent optionality?
the best example of it i can find is here...
basically a black dot or white dot represent optional or mandatory.
can anyone tell me if this type of erd has a specific name and if there are examples of this in any books you know of?
and here...
cheers,
the best example of it i can find is here...
basically a black dot or white dot represent optional or mandatory.
can anyone tell me if this type of erd has a specific name and if there are examples of this in any books you know of?
and here...
cheers,