What is the difference between....

Just wondered, what is the difference between a cardinality ratio
constraint and a structural constraint?

Is, a cardinality ratio like 1-to-many, 1 to 1 etc..
and
Structural constraint has (min, max) values? (for each relation?)

e.g. Cardinality Ratio:
Each car must have one registered owner, but an owner can have sevaral
cars
Owner-------<owns>--------------Car
1 M

e.g. Structural Constraint:
Each employee must work in 1 department, but a department can only have
4 employees

Employee -----------<must work>-------------Department
(1,1) (1,4)



PS: Apologies, Google wont let me use tabs....

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