Complex Attributes UML Diagrams

Question

Just had to look into "Complex Attributes", admittedly I'm not an expert when it comes to this area but I was just wondering if this was in fact a correct "Complex Attribute" however pathetic is may be deemed. (I'm just trying to grasp basic knowledge for now!). Just found out I can't post pictures so... Here goes.

Entity - Car.
Attribute - RegNum
Attribute - Year

Entity - Tyres
Attribute - NumberOfTyres
(COMPLEX ATTRIBUTE?) - TyreBrand[0..*]

Insinuating the tyres could have multiple brands?

Regards.

Answer 1

You are right

Entity - Tyres Attribute - NumberOfTyres (COMPLEX ATTRIBUTE?) - TypeBrand[0..*]

Express the fact that a "Types" object could have multiple "Typebrand".

Regards,

BR

Answer 2

The UML spec makes no mention of "complex attribute"; however, the multiplicity expressed within square brackets in TyreBrand[0..*] is indeed the way to specify that a Tyre can have zero or more TyreBrand values.

Be careful with your terminology, though. When one uses the term "complex attribute", it usually describes whether an attribute's type has a simple or complex structure. For example, a phone number can be stored as a scalar String value (e.g., "+1 800-555-5555") or as a complex Telephone Number datatype with its own country code, area code, exchange, and station attributes of type String (e.g., "+1", "800", "555", "5555"). Just to be clear, a Telephone Number datatype would look like a class on a diagram, but with the «datatype» keyword at the top. It can be used as an attribute type instead of String.