Hello Bruno,
Karen Tracey solved my issue and now i will be able to apply those
refactoring you suggested me.
Thanks for tips :-)
Att
Thiago
On Jan 19, 7:18 pm, bruno desthuilliers
<bruno.desthuilli...@gmail.com> wrote:
> On 19 jan, 18:04, "Thiago F. Crepaldi" <togn...@gmail.com> wrote:
>
> Absolutely not an answer to your question, but...
>
> > below is the code required. I hope you can help me =)
>
> #*****************************************************************************************************************************************************************
>
> > # searchFeature
>
> #*****************************************************************************************************************************************************************
>
> > def searchFeature(request, view = None):
> > if request.method == 'POST':
> > form = SearchFeatureForm(request.POST)
> > if form.is_valid():
> > # Perform the query
>
> > ftrQuery = Feature.objects.all().order_by('featureId',
> > 'pk')
>
> Since your going to filter this out, starting by querying all is
> useless (thanks to querysets being lazy, it's at least _only_ useless.
>
> Remember that Django has Q objects for building complex queries, and
> that you can just collect Q objects in a list, then "or" or (like in
> this case) "and" them together in just one pass.
>
>
>
> > # Remove empty fields and start filtering
> > if request.POST.__getitem__('featureId') != "":
>
> First point : you should never directly access __magic_methods__ in
> Python - they are here as implementation for operators. In this case,
> you want:
>
> if request.POST.get('featureId', '') != '':
>
> Second point: since empty strings eval to false in a boolean context,
> you don't have to explicitely compare them with the empty string. IOW:
>
> if request.POST.get('featureId, ''):
>
> > ftrQuery = ftrQuery.filter(featureId__contains =
> > request.POST.__getitem__('featureId')).distinct()
>
> Third point : you're doing the same access twice. Better to do it just
> once:
>
> featureId = request.POST.get('featureId, '')
> if featureId:
> # code here
>
> While we're at it, attribute lookup is a somewhat costly operation in
> Python, specially when the attribute resolves to a method. So if
> you're going to heavily use the same method of the same object, it's
> better to alias it to a local name:
>
> get_from_post = request.POST.get
>
> featureId = get_from_post('featureId, '')
> if featureId:
> # code here
>
> While we're at it : your form object is supposed to give you access to
> the validated (and possibly converted) data extracted from the
> request. Is there any reason to not use this feature ?
>
> Next point : you can pass dict objects to Queryset.filter(), (or to Q
> objects) using the ** notation (cf the section of the official Python
> tutorial about functions and named / keyword arguments). So you could
> greatly simplify you code:
>
> filters = [
> # fieldname, lookup
> ("featureId", "featureId__contains"),
> ("name", "name__icontains")
> ("pf", "platform"),
> ("state", "state"),
> ("db", "drumbeat__pk"),
> # etc
> ]
>
> queries = []
> add_q = queries.append
> for fieldname, lookup in filters:
> value = get_from_post(fieldname, '')
> if value:
> add_q(Q(**{lookup:value}))
>
> # now "and" the Q objects:
> filters = reduce(lambda q1, q1 : q1 & q2, filters)
>
> # and do the query:
> if filters:
> queryset = Feature.objects.filter(filters)
> else:
> queryset = Feature.objects.all()
>
> queryset = queryset.order_by('featureId', 'pk')
>
> This can not apply to all your query construction (there are some
> complex cases in it), but it should already help uncluttering it for
> all the simple cases.
>
> (snip)
>
> > from datetime import date
>
> Better to put import statements at the module's top-level.
>
> > #Only way I could find to select with COUNT without
> > writting the SQL code.
>
> You might have a look at the example snippet for the 'extra' method of
> querysets.
>
> > if queryTeamSizeLow != '':
> > for item in ftrQuery:
> > if item.teammember_set.count() < int
> > (queryTeamSizeLow):
>
> Oh my. Pity this poor computer, and at least convert queryTeamSizeLow
> to an int only once...
>
> > ftrQuery = ftrQuery.exclude
> > (featureId=item.featureId)
>
> > if queryTeamSizeHigh != '':
> > for item in ftrQuery:
> > if item.teammember_set.count() > int
> > (queryTeamSizeHigh):
> > ftrQuery = ftrQuery.exclude
> > (featureId=item.featureId)
>
> Ok. Some things are better done building raw sql queries. Django's ORM
> is here to help with the easy and boring 80%, not to replace SQL.
>
> My 2 cents...
>
> (snip)
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