On 5 mar, 12:02, Grupo Django <[EMAIL PROTECTED]> wrote:
> On 5 mar, 11:25, Evert Rol <[EMAIL PROTECTED]> wrote:
>
>
>
> > >>> I need to optimize some code related to django db api.
> > >>> Imagine a model like this:
>
> > >>> class Languages( models.Model ):
> > >>> name = models.CharField( max_length=255 )
> > >>> ...
>
> > >>> class Object ( models.Model ):
> > >>> name = models.CharField( max_length=255 )
> > >>> languages = models.ManyToManyField( Languages, radio_admin=True )
>
> > >>> I need to create a form to search Objects:
> > >>> def my_view(request):
> > >>> ...
> > >>> if request.POST:
> > >>> form = MyForm( request.POST )
> > >>> if form.is_valid():
> > >>> data = form.cleaned_data
> > >>> objects = Object.objects.all()
> > >>> if data['name']:
> > >>> objects = objects.filter( name__icontains =
> > >>> data['name'] )
> > >>> if data['languages']:
> > >>> (1)
> > >>> ...
>
> > >>> I need to search an Object with name ILIKE %name% and with the
> > >>> languages specified in the form. data['languages'] looks like:
> > >>> [ u'1',u'2' ] the IDs of each language.
>
> > >>> I needs some help with the code that should be placed in (1).
> > >>> I thought:
> > >>> ----
> > >>> for language in languages:
> > >>> objects = Object.filter( languages__id = language)
>
> > >> Have a look at 'in'
> > >> filtering:http://www.djangoproject.com/documentation/db-api/#in
> > >> Maybe that can help you out. The code above is certainly not going to
> > >> work, because you try on the model, not the results returned from the
> > >> managaer. Besides, you'd be filtering in an 'AND' combination, not
> > >> 'OR'
>
> > > I can't use IN because it returns an Object that has any of the
> > > languages requested.
>
> > Sorry, then I missed what you're trying to achieve; I guessed you
> > wanted to have all languages specified by the form (shouldn't 'IN'
> > return that?), and you can then filter those on the name by appending
> > a .filter() to the returned QuerySet.
> > At least, that's what I thought you wanted and would work.
>
> > > The SQL clause I need is:
> > > select DISTINCT ... from app_object_languages as m2m INNER JOIN
> > > app_object as ob ON ob.id = m2m.object_id where ( m2m.language_id=1 or
> > > m2m.language_id=2);
>
> > > I can't get it!
> > > Thank you for your help.
>
> Well, my English is far from perfect, and I'm not really sure what you
> mean, but what I want is to retrieve all the objects that have the
> lenguages of the form.
> i.e.
> There are 2 languages in the model Language: English and Spanish.
> o1 is an object with two relations to languages English and Spanish
> 02 is an object with only one relation to language English
> I need to get all the Objects that have English and Spanish, so only
> o1 should be retrieved.
> I hope this is clearer, sorry about the misunderstanding, sometimes
> it's hard to say what I think :-)
> Thank you.
I think I solved the problem:
for language in data['languages']:
objects = objects.extra(where=["EXISTS ( SELECT 0 FROM
app_object_languages as m2m WHERE m2m.object_id = app_object.id AND
m2m.language_id = %s )",], params=[ idioma ])
Thank you for your help.
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