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Tag "queryset"

39 snippets

Snippet List

SearchableManager

A drop-in chainable manager for providing models with basic search features such as +/- modifiers, quoted exact phrases and ordering by relevance.

  • search
  • model
  • manager
  • queryset
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Case-insensitive lookup by default

I wanted lookups on tags to be case insensitive by default, so that things like Tag.objects.get(name='Tag') would return any similar tags (ignoring case differences), i.e. `<Tag: tag>`. This snippet makes lookup on the 'name' field case-insensitive by default, although case-sensitive lookups can still be achieved with 'name__exact'. Methods like get_or_create will work as expected and be case-insensitive.

  • model
  • tags
  • tagging
  • manager
  • case-insensitive
  • iexact
  • queryset
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Chain multiple querysets into one

This class acts as a wrapper around multiple querysets. Use it if you want to chain multiple QSs together without combining them with | or &. eg., to put title matches ahead of body matches: >>> qs1 = Event.objects.filter(## title matches ##) >>> qs2 = Event.objects.filter(## matches in other fields ##) >>> qs = MultiQuerySet(qs1, qs2) >>> len(qs) >>> paginator = Paginator(qs) >>> first_ten = qs[:10] It effectively acts as an immutable, sliceable QuerySet (with only a very limited subset of the QuerySet api)

  • queryset
  • chain
  • multi
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(Modified/Improved) MultiQuerySet

My modified version of the [MultiQuerySet by mattdw](http://www.djangosnippets.org/snippets/1103/) (see the link for further information). My purpose for this was to enable me to combine multiple different types of querysets together, which could then be iterated on as one object (i.e. like a tumblelog).

  • multiple
  • queryset
  • chain
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Lazy options on ModelForm fields - like setting a ModelChoiceField queryset from the view

Example view code: lazy_field_options = { 'field_name_that_is_m2m': { 'queryset': YourRelatedModel.objects.filter(groups=request.user.groups.all()), }, 'field_name_that_is_fk': { 'queryset': YourOtherRelatedModel.objects.filter(slug=request_slug), }, } modelform = YourModelForm(jpic_field_options=lazy_field_options) # after the modelform has called for parent __init__, it will set # options for each field if possible.

  • hack
  • form
  • queryset
  • modelchoicefield
  • modelform
  • modelmultiplechoicefield
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Pretty print SQL of query sets

Install [sqlparse](http://code.google.com/p/python-sqlparse/) with `easy_install sqlparse` and then you can easily debug the SQL like this: def view(request): data = MyModel.objects.filter(something__very=complex) print_sql(data) ... Inspired by [Simon Willison](http://simonwillison.net/2009/Apr/28/)

  • sql
  • queryset
  • sqlparse
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Override QuerySet.delete() (one way of preventing cascading deletes)

We needed to override the default QuerySet delete function to deal with a client problem that we were facing Yes This is monkey-patching, and probably bad practice but if anyone needs to conditionally override the cascading delete that django does at the application level from a queryset, this is how to do it

  • queryset
  • delete
  • monkey-patch
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TaggedManager and TaggedQuerySet with chainable tagged() methods implemented with django-tagging

The popular [django-tagging](http://code.google.com/p/django-tagging/) app has, in its implementation and semantics, a highly usable and transparent elegance -- but then you have to call methods on a Tag instances' items collection. These classes let you inline the tag name in the chain of queryset filter methods instead. TO USE: ### models.py ... from tagging.fields import TagField from tagging.models import Tag as Tag class YourModel(models.Model): ... yourtags = TagField() objects = TaggedManager() ... ### and then elsewhere, something like-- ... ym = YourModel.objects.order_by("-modifydate")[0] anotherym = YourModel.objects.get(id=7) ## distinct from ym ym.yourtags = "tag1 tag2" anotherym.yourtags = "tag1 othertag" ym.save() anotherym.save() with_tag1 = YourModel.objects.tagged('tag1') with_tag2 = YourModel.objects.tagged('tag2').order_by('-modifydate') print ym in with_tag1 ## True print anotherym in with_tag1 ## True print ym in with_tag2 ## False ... since these are QuerySets, you can easily create unions (e.g. `with_tag1 | with_tag2` and othersuch) as you need and filter them to your hearts' content, without having to instantiate Tag all the time (which you can of course do as well).

  • manager
  • queryset
  • django-tagging
  • django1.1
  • chainable
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Bitwise operator queryset filter

This snippet for django-1.2 allows you to use bitwise operators without using QuerySet.extra() from django.db.models import * from somewhere import FQ class BitWise(Model): type = CharField(max_length=8) value = IntegerField() def __unicode__(self): return '%s - %d' % (self.type, self.value) >>> BitWise.objects.create(type='django', value=1) <BitWise: django - 1> >>> BitWise.objects.create(type='osso', value=3) <BitWise: osso - 3> >>> BitWise.objects.create(type='osso', value=7) <BitWise: osso - 7> >>> BitWise.objects.filter(FQ(F('value') & 1, 'gt', 0)) [<BitWise: django - 1>, <BitWise: osso - 3>, <BitWise: osso - 7>] >>> BitWise.objects.filter(FQ(F('value') & 2, 'gt', 0)) [<BitWise: osso - 3>, <BitWise: osso - 7>] >>> BitWise.objects.filter(FQ(F('value') & 1, 'gt', 0) & Q(type='django')) [<BitWise: django - 1>]

  • filter
  • queryset
  • bitwise
  • operator
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