python sql query in django

I have three tables:

class Technology(models.Model):
technology = models.CharField(max_length=100, null=True,
blank=True )
def __unicode__(self):
return self.technology
class Meta:
ordering = ["technology"]

class Publication(models.Model):
pubtitle = models.TextField(null=True, blank=True)
def __unicode__(self):
return self.pubtitle
class Meta:
ordering = ["pubtitle"]

class Techpubcombo(models.Model):
technology = models.ForeignKey(Technology)
publication = models.ForeignKey(Publication)

The user selects a technology from the drop down menu on the web
page. The technology is retrieved
from the database table and then it must be used to retrieve the
publication attributes, by first going through the Techpubcombo table.

I wrote the select to retrieve the data for the html drop down box:
technology_list = Technology.objects.all().order_by('technology')

After the user makes a selection, the technology_id is retrieved:
technology_id = request.POST['technology_id']
t = get_object_or_404(Technology, pk=technology_id)

Now I need to use the technology_id to get to the publication
attributes

This is where I'm stuck.

I get error messages when I try to do something like:

pub=t.techpubcombo.publications_set()

Ana

May

May a écrit :
> I have three tables:

Actually - from Python's code POV - three Model classes. And actually,
since there's a very active, friendly and helpful django group on
googlegroups, you'd be better reposting your question there.

(snip Django's ORM related question)

Bruno Desthuilliers

On Feb 23, 11:31*am, Bruno Desthuilliers
<bdesth.quelquech...@free.quelquepart.fr> wrote:
> May a écrit :
>
> > I have three tables:
>
> Actually - from Python's code POV - three Model classes. And actually,
> since there's a very active, friendly and helpful django group on
> googlegroups, you'd be better reposting your question there.
>
> (snip Django's ORM related question)

The django users groups suggests using a manytomany field. That works
well in the html template, but in the admin tables, the logic for the
manytomany field applies to the wrong model and doesn't create a
choice for the data entry people. I'm trying to write this without
using the manytomany option. Just using the standard relational
database model. I need to understand if python can do what I need to
do. So far, I've not been successful with an answer in users groups.

Ana

May

May a écrit :
(snip)
> I may not stay with Django.

Nope, but your question was about Django.

> I am seriously looking for whether python
> can read data from a relational database

Of course - as long as there's a Python adapter for your DB.

> and send to an html template

Of course - as long as it's either a Python templating system or there's
a Python binding for this system.

> or do I always need some kind of wrapper/interface such as Rails

Uh ? Rails is a Ruby framework.

> or
> Django?

No, you don't. If you prefer to reinvent the wheel on each and any part
of each an any web app you write, please feel free to do so.

> If this is the wrong group to ask that question

Which "that" question ?-)

For question related to Django's ORM, the django group is indeed a
better place (as usual: always use the most specific group / maling list
/ whatever first). If you have questions (like the above) that are about
Python itself, you're at the right place.

Bruno Desthuilliers

May wrote:
> On Feb 23, 11:31 am, Bruno Desthuilliers
> <bdesth.quelquech...@free.quelquepart.fr> wrote:
>> May a écrit :
>>
>>> I have three tables:
>> Actually - from Python's code POV - three Model classes. And actually,
>> since there's a very active, friendly and helpful django group on
>> googlegroups, you'd be better reposting your question there.
>>
>> (snip Django's ORM related question)
>
> The django users groups suggests using a manytomany field. That works
> well in the html template, but in the admin tables, the logic for the
> manytomany field applies to the wrong model and doesn't create a
> choice for the data entry people. I'm trying to write this without
> using the manytomany option. Just using the standard relational
> database model. I need to understand if python can do what I need to
> do. So far, I've not been successful with an answer in users groups.
>
I am sure if you explain in detail exactly what you want the admin to
present to your data entry people there are those on django-users who
can help you make it happen. That list *would* be the best place to get
an answer: this one mostly discusses the Python language in a more
generic manner.

regards
Steve
--
Steve Holden +1 571 484 6266 +1 800 494 3119
Holden Web LLC http://www.holdenweb.com/

Steve Holden

On Feb 23, 1:00*pm, Steve Holden <st...@holdenweb.com> wrote:
> May wrote:
> > On Feb 23, 11:31 am, Bruno Desthuilliers
> > <bdesth.quelquech...@free.quelquepart.fr> wrote:
> >> May a écrit :
>
> >>> I have three tables:
> >> Actually - from Python's code POV - three Model classes. And actually,
> >> since there's a very active, friendly and helpful django group on
> >> googlegroups, you'd be better reposting your question there.
>
> >> (snip Django's ORM related question)
>
> > The django users groups suggests using a manytomany field. *That works
> > well in the html template, but in the admin tables, the logic for the
> > manytomany field applies to the wrong model and doesn't create a
> > choice for the data entry people. *I'm trying to write this without
> > using the manytomany option. *Just using the standard relational
> > database model. *I need to understand if python can do what I need to
> > do. *So far, I've not been successful with an answer in users groups.
>
> I am sure if you explain in detail exactly what you want the admin to
> present to your data entry people there are those on django-users who
> can help you make it happen. That list *would* be the best place to get
> an answer: this one mostly discusses the Python language in a more
> generic manner.
>
> regards
> *Steve
> --
> Steve Holden * * * *+1 571 484 6266 * +1 800 494 3119
> Holden Web LLC * * * * * * *http://www.holdenweb.com/

I may not stay with Django. I am seriously looking for whether python
can read data from a relational database and send to an html template
or do I always need some kind of wrapper/interface such as Rails or
Django? If this is the wrong group to ask that question could you
recommend another python group that could?

Thanks.

May

> I may not stay with Django. I am seriously looking for whether python
> can read data from a relational database and send to an html template
> or do I always need some kind of wrapper/interface such as Rails or
> Django? If this is the wrong group to ask that question could you
> recommend another python group that could?

Python itself comes neither with an ORM, nor with a HTML
generating/mapping framework.

So yes, if you want something like that, need something like rails or
django. Or TurboGears.

For example, you can use SQLAlchemy as ORM, and RUM as frontend for it.
I'm not sure if it fullfills your requirements though.

http://python-rum.org/

Diez

Diez B. Roggisch

On Feb 23, 2009, at 4:34 PM, Diez B. Roggisch wrote:

>> I may not stay with Django. I am seriously looking for whether
>> python
>> can read data from a relational database and send to an html template
>> or do I always need some kind of wrapper/interface such as Rails or
>> Django? If this is the wrong group to ask that question could you
>> recommend another python group that could?
>
> Python itself comes neither with an ORM, nor with a HTML generating/
> mapping framework.
>
> So yes, if you want something like that, need something like rails
> or django. Or TurboGears.
>
> For example, you can use SQLAlchemy as ORM, and RUM as frontend for
> it. I'm not sure if it fullfills your requirements though.

And if you don't like ORMs, most databases have at least one adapter
out there that allows one to send straight SQL to the DB engine and
get results back in some useful form. For instance, there's the
psycopg2 adapter for talking to Postgres. Python has a built-in
wrapper for SQLite.

Philip Semanchuk

On Feb 23, 12:48*pm, Bruno Desthuilliers
<bdesth.quelquech...@free.quelquepart.fr> wrote:
> May a écrit :
> (snip)
>
> > I may not stay with Django.
>
> Nope, but your question was about Django.
>
> > I am seriously looking for whether python
> > can read data from a relational database
>
> Of course - as long as there's a Python adapter for your DB.
>
> > and send to an html template
>
> Of course - as long as it's either a Python templating system or there's
> a Python binding for this system.
>
> > or do I always need some kind of wrapper/interface such as Rails
>
> Uh ? Rails is a Ruby framework.
>
> > or
> > Django? *
>
> No, you don't. If you prefer to reinvent the wheel on each and any part
> of each an any web app you write, please feel free to do so.
>
> > If this is the wrong group to ask that question
>
> Which "that" question ?-)
>
> For question related to Django's ORM, the django group is indeed a
> better place (as usual: always use the most specific group / maling list
> / whatever first). If you have questions (like the above) that are about
> Python itself, you're at the right place.

Thanks for all your suggestions. From what I've experienced in Django
and now that I know a little more about how Python functions, I will
probably use a combination of PHP and Django, instead of trying to get
Python to do the web portion of my project. Thanks again!

May

>
> Thanks for all your suggestions. From what I've experienced in Django
> and now that I know a little more about how Python functions, I will
> probably use a combination of PHP and Django, instead of trying to get
> Python to do the web portion of my project. Thanks again!

That sounds like the worst idea. Django's ORM is good when used from
within django, because of all the additional goodies like the admin
interface.

But if you are going to do the webfrontend using PHP, what part is left
for django? If it's only the ORM (for whatever you still use that
anyway), there are better alternatives - SQLAlchemy, and SQLObject, for
Python. They are more powerful and not interwoven with django.


If you are going to hand-code the interface in PHP, I fail to see though
why you don't do that in Django directly. You are not forced to use the
Admin-interface.

Diez

Diez B. Roggisch