Re: users and profiles - model structure question
On Fri, 2008-04-18 at 11:02 +0100, andy baxter wrote: [...] > Has anyone dealt with this problem in practice, and do people have any > thoughts about what is the best way of doing things here, from the point > of view of keeping the code simple, and also minimising the time spent > doing database lookups? (I'm guessing that looking up a User from a > Member is slightly quicker than looking up a Member from a User). This is kind of an interesting problem and I've come across it twice recently and ended up going with different approaches each time. Firstly, to get rid of one source of confusion, there is no difference traversing from User -> a profile or vice-versa. Both require a table join at the database level. If you're splitting hairs on the difference at the Python code level, it's so minor (and so varied) that something is seriously wrong if you notice it. So that (direction) should not be a consideration at all. In both my cases, I originally tried to puzzle out what would be the "obvious, right" way, but it only became clearer after I started writing code. In one case, most of the uses of the User+Profile pair was dealing with aspects of the standard user model (auth stuff, permissions and things like that), so I mostly needed to access User. In the other case, I was mostly referring to the profile object and so the many, many models I have linking back to the "user" link to this profile: because I primarily need the extra information. I'm still not sure I could have completely puzzled this out in advance, without more or less writing the code in my head. That's kind of the cost (and benefit) of rapid development: you can happily try something out and change a little later. On the first project (where I end up pointing to User), it became clear fairly quickly that the User model was the right one. In the second case, I vacillated a fair bit and changed my mind more than once over a three or four day period. The fact that it was such a line ball also convinced me it probably wasn't that big a deal. My time budget isn't being predominantly spent on the User/Profile joins and lookups, it's going elsewhere. So it probably wouldn't have mattered much and at some point I made a conscious decision to stop worrying about that and move on. It was starting to dominate my thinking a bit too much. Regards, Malcolm -- I intend to live forever - so far so good. http://www.pointy-stick.com/blog/ --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~--~~~~--~~--~--~---
Re: users and profiles - model structure question
andy baxter wrote:
> Alex Koshelev wrote:
>
>> I usually make link to User model not profile. And have no problems
>> with usage.
>>
>>
>>
> I just tried switching to this way of doing it, and have come up against
> a problem with getting the profile data into the template. If I create a
> list of all users in the view, then pass the list of users to the
> template as user_list, I would like to be able to iterate over the list
> using '{% for user in user_list %}', and then retrieve the data from the
> profile inside the template. I tried doing {{
> user.get_profile.self_description }}, which is meant to retrieve the
> self_description field from the Member object associated with the given
> User. But this raises a template error: 'Too many values to unpack'
>
> Is it possible to refer to profile data in the template like this, or do
> I need to find another way to do it?
>
>
Sorry, forget that - I just had AUTH_PROFILE_MODULE set wrong. Now it's
working OK.
andy.
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Re: users and profiles - model structure question
Alex Koshelev wrote:
> I usually make link to User model not profile. And have no problems
> with usage.
>
>
I just tried switching to this way of doing it, and have come up against
a problem with getting the profile data into the template. If I create a
list of all users in the view, then pass the list of users to the
template as user_list, I would like to be able to iterate over the list
using '{% for user in user_list %}', and then retrieve the data from the
profile inside the template. I tried doing {{
user.get_profile.self_description }}, which is meant to retrieve the
self_description field from the Member object associated with the given
User. But this raises a template error: 'Too many values to unpack'
Is it possible to refer to profile data in the template like this, or do
I need to find another way to do it?
andy
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Re: users and profiles - model structure question
I usually make link to User model not profile. And have no problems with usage. On Apr 18, 2:02 pm, andy baxter <[EMAIL PROTECTED]> wrote: > Hello, > > I have built a data model for a virtual library, which contains the > following classes (among others): > > User - the built in user class from django.contrib.auth. > Member - a profile for each user, containing extra information about > each member. > Item - a book, video, or music album > Iteminstance - a specific copy of an item. > > I am thinking about what is the best way to structure this data - in > particular if ForeignKey fields from other tables (like iteminstance) > should refer to the Member table or the User table. At the moment I have > it like this: > > Member.user -> User > ItemInstance.owner -> Member > ItemInstance.item -> Item > > But I'm not sure about the second of these - should it be > ItemInstance.owner->User? > > I'm getting the feeling as I'm starting to write the code dealing with > Members and Users that making the right choice here could be important, > so as not to have to end up writing unnecessarily tangled code as the > model develops in the future (e.g. if I add 'Review' which refers to an > Item and is made by a Member/User). > > Has anyone dealt with this problem in practice, and do people have any > thoughts about what is the best way of doing things here, from the point > of view of keeping the code simple, and also minimising the time spent > doing database lookups? (I'm guessing that looking up a User from a > Member is slightly quicker than looking up a Member from a User). > > andy --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups "Django users" group. To post to this group, send email to django-users@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/django-users?hl=en -~--~~~~--~~--~--~---
