On 25 Apr., 21:40, "Marty Alchin" <[EMAIL PROTECTED]> wrote:
>
> Not to get too much into this discussion, but I tend to be slow to
> understand design patterns and other paradigms. What then would be the
> appropriate way to handle an app that managed authors? I can see two
> possibilities:
>
> class Author(User):
> pen_name = models.CharField(max_length=255)
>
> or
>
> class AuthorProfile(models.Model):
> user = models.OneToOneField(User)
> pen_name = models.CharField(max_length=255)
>
> Essentially, whether it has the semantics of an "is-a" or a "has-a"
> relationship seems to depend solely on what name I give the class.
> Clearly a user could "be an" author, while he/she could instead "have
> an" author profile.
>
> How would I proceed in a situation like this?
I would tend to subclassing in this case. To make my point clear add
another user model called "Reader" to the example:
class Reader(User):
stories_read = models.IntField()
Assuming that only author's should have a "pen_name" and only readers
should have a "stories_read" field, it would be feeling "not
naturally" to put these fields in a profile (and therefore go the
profile way).
Furthermore assuming that your site requires *every* user (readers and
authors) to specify their phonenumber (which is not part of standard
User model), this should go into a profile:
class UserProfile():
user = models.OneToOneField(User)
phone = models.PhoneField()
That way you benefit from both. You have Authors and Readers which are
users ("is-a"), and which both have a phone number ("has-a").
>From an OO standpoint you are now able to use Authors and Readers
instances, whereever a User instance is used in the API. This is not
possible when using a profile.
Please be aware that I did not test the qsrf branch and the examples
above and the way I understand things are maybe not how things work.
peschler
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