HOPEX Information Architecture > Data Architecture > The data model > Normalization Rules > First Normal Form
First Normal Form
 
Rule: The value of an attribute is uniquely set when the object(s) concerned are known.
If the number of vehicles is an attribute of the “Reservation” entity, you can only indicate the total number of vehicles for a reservation. You must therefore make one reservation per category of rental vehicle (multiplicity of 1).
If the number of vehicles is an attribute of the association, you can specify the number of vehicles reserved for each category in the association. You can therefore make a single reservation for several categories of vehicles (multiplicity of 1..N).