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You can include references to any other objects or classes that you want to extend, inherit, or
otherwise manipulate, and you can write any methods for which you want this class to provide
functionality. However, it??™s important to remember that you must at least define the attributes
you specified in the mapping parameter and an initialize method, or your class really won??™t
know how to collect the database information into an object state.
Once again, an example helps explain the details a little better, so let??™s create a value object
for some basic song information. To make things a little more interesting than just grouping
things together, we??™ll also define a method that lets us automatically get all the songs of the
same name as the current record but recorded by other artists. Here??™s our new value object:
class Songinfo
attr_reader :artist, :songtitle, :songlength
def initialize(artist, songtitle, songlength)
@artist, @songtitle, @songlength = artist, songtitle, songlength
end
def by_other_artist
Song.


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