On Jan 14, 2010, at 11:53 PM, E. Hakan Duran wrote: > Thanks a lot for the quick response. > > On Thursday 14 January 2010 23:08:43 Shawn Milochik wrote: > >> ... >> woman = Woman.objects.get(lastname__exact = 'Test') >> couple = Couple.objects.get(couple = woman.couple) >> >> Note that this is making the assumption that there is only one woman with >> that last name, and that there is only one couple with this woman in it. > > And that may not be the case. In my example, there are 2 women with the same > last name and I would like to get their couple ids individually, which will > then enable me to get their relevant info from Couple model. Do you think it > is possible to do that?
women = Woman.objects.filter(lastname__exact = 'Test')
Then return that in the context, and you can iterate through 'woman' in your
template, referring to woman.firstname, woman.couple.address1, etc.
>
>> I don't know if you just made this up as an example, but if it's something
>> that you're actually working on, it seems like making a Woman and Man
>> model isn't a very good idea because there's so much duplication. Just
>> have a Person model with a 'sex' field, and you have have a foreign key to
>> itself labeled 'partner' or something. No need for a separate 'couples'
>> table. If you really need the address info, there should be an Address
>> model. After all, you may have other things (businesses, etc.) that also
>> have addresses which will require the same validation. It gets really ugly
>> really fast when you have 'address1, address2, city, state, and zip' in a
>> bunch of different models. Possibly with different field lengths and other
>> stuff.
>
> Thanks for the really very useful suggestions. I didn't think it that way
> really, but how about duplicate home addresses for the man and woman living
> together? Wouldn't there be a lot of redundant data that way? Would you mind
> recommending me some documentation to learn about foreign key to itself? I am
> not sure that I understand how it is set up.
Multiple addresses: Easy. Many-to-many relationship is one option, or a generic
foreign key in the Address model.
Foreign key to self: partner = models.ForeignKey('self', null=True,
related_name='spouse')
http://docs.djangoproject.com/en/dev/ref/models/fields/#foreignkey
>
>> Also, I don't know what you mean by not having a technical background, but
>> if you mean you have no application design or programming experience, then
>> I urge you to hire someone to do this, unless this is just something
>> you're doing to teach yourself to program (and if so, welcome!). Despite
>> the fact that Python and Django are far less daunting to learn than other
>> tools, they still require programming ability to do at all, and a lot of
>> experience to do well. Nothing personal -- I just wanted to point out that
>> database design and application design are definitely not trivial and
>> shouldn't be done by someone with no experience if this is something
>> needed by your business.
>
> Thanks for the fair warning Shawn. I cannot agree more. Although this looks
> like a business database set up, I have no intention to use it in a business
> setting. This will probably be my hobby project that I develop in my spare
> time over several months probably. I am well aware of the risks of collecting
> and storing personal information, let alone putting them on an online server
> without the expertise and experience of programming and security. Even if I
> believed I had those qualities, I would still not attempt to do that with
> this
> kind of information. I am just challenging myself with a very difficult task
> for
> my level, to learn python and django and gain some comfort in using them. I
> truly appreciate your sincere and rightful warnings.
Cool. Everyone starts the same way. Or they should -- learning by having a goal
and figuring out how to achieve it.
>
> Regards,
>
> Hakan
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