| 4.3. Relationships | ||
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 | Chapter 4. Lists |  |
| 4.3. Relationships | ||
|---|---|---|
| | Chapter 4. Lists | |
[ fromfile: relationships.xml id: relationships ]
In Figure 4.1, the line connecting the classes expresses a particular relationship between them.
In the context described by this diagram, there can be many Person instances working for exactly one Employer.
This can be denoted by the multiplicity specifier at each end of the relationship: 1 at the Employer end, and * at the Person end.
The * takes on its regular expression definition, of "0 or more" (Section 14.3).
There is a composition relationship (the filled diamond) between Employer and Position.
It indicates that the Employer owns or manages the Position, and the Position should not exist without the Employer.
There is an aggregation relationship (the empty diamond) from the Employer to its employees.
The Employer groups together a collection of Persons and gets them to do things during working hours.
In an aggregation relationship, the lifetimes of the objects on either end are not related to one other.
The Person and the Position have a bidirectional assocation between them.
| Generated: 2012-03-02 | © 2012 Alan Ezust and Paul Ezust. |
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4.2.2. QDir, QFileInfo, QDirIterator |  | 4.3.1. Relationships Summary |
