Study Cards on association, place, attribute
Normally, we do not use both formats for the same property because it can get confusing (and redundant).
A Book has a read-only, ordered set of many authors who are Persons
or
A Book has an ordered set of many Persons in the role of authors
In Table 10.2, we show almost all the possible adornments for an Attribute.
So a 0..1 is an optional field, 0 is a field that cannot appear
0..* indicates the notation can appear as often as you need.
The order shown is the approximate order that they can appear.
• AggregationKind (normally shown only on an association), which we cover later
• Qualifiers (normally shown only on an association), but are not on the first exam
• Multiplicity brackets (used on attributes but not on an association)
• Default value (normally only on an attribute)
Using the association form is most common when the property is a class (rather than a datatype).
The individual classes (or dataTypes) now can be further connected to classes, and the diagrams indicate a fuller picture of their relationships
What do we see in the figure?
For example:
the Person Class can have a forename, a surname, and a date span
Moreover, a Person Class can have relationships of their own.
See Fig. 10.16. In this example, a Person can also be both a composer of a Score and an author of a Book
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