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Django Queryset

Subject : it-skills

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Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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This is a study tool. The 3 wrong answers for each question are randomly chosen from answers to other questions. So, you might find at times the answers obvious, but you will see it re-enforces your understanding as you take the test each time.

1. By default - results returned by a QuerySet are ordered by the ordering tuple given by the ordering option in the model's Meta. You can override this on a per-QuerySet basis by using the this method.
Manager methods
Meta class
&
order_by(*fields)

2. The first element in this iterable is the value that will be stored in the database - the second element will be displayed by the admin interface - or in a ModelChoiceField.
choices tuple
unique
Model metadata
class type

3. Returns a new QuerySet containing objects that match the given lookup parameters.
filter(**kwargs)
__unicode__()
order_by(*fields)
choices tuple

4. Lookup type that tests for inclusion in a case-sensitive fashion.
isnull
pickling
contains
Model metadata

5. Defines a many-to-many relationship. You use it just like any other Field type: by including it as a class attribute of your model.
many-to-many relationship
ManyToManyField
Manager
Field lookups

6. This field is added automatically - but this behavior can be overridden
id field
when you add new apps to INSTALLED_APPS
get(**kwargs)
__unicode__()

7. Returns the object matching the given lookup parameters
delete()
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
class type
get(**kwargs)

8. Accomplish this by using the field name of related fields across models - separated by double underscores - until you get to the field you want. For example - to get all Entry objects with a Blog whose name is 'Beatles Blog': Entry.objects.filter(blo
Entry.objects.filter(id__in=[1 - 3 - 4])
through argument
Q()
relationship spanning

9. Used to get a QuerySet for a model. This is called 'objects' by default.
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
db
get(**kwargs)
Manager

10. Lookup type that returns results with a case-sensitive end sequence.
get(**kwargs)
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
only(*fields)
endswith

11. Lookup type that returns results in a given list.
in_bulk(id_list)
distinct()
select_related()
in

12. Each one of these is a Python class that subclasses django.db.models.Model. Each attribute of one of these represents a database field.
Entry.objects.filter(id__gt=4)
filter(**kwargs)
model
evaluation

13. This query uses an F object to increment the pingback count for every entry in the blog.

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

14. This tells Django how to calculate the URL for an object. Django uses this in its admin interface - and any time it needs to figure out a URL for an object.
aggregate(args - *kwargs)
get_absolute_url()
relationship spanning
iregex

15. These methods are intended to do "table-wide" things.
help_text
Manager methods
all()
iteration

16. To activate your models
lte
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
MultipleObjectsReturned
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)

17. Disjunction operator for Q objects.
F()
Q()
ManyToManyField
|

18. Lookup type for date/datetime fields that finds an exact day match.
Model metadata
day
Entry.objects.filter(id__gt=4)
MultipleObjectsReturned

19. A convenience method for looking up an object with the given kwargs - creating one if necessary.
delete()
get_or_create(**kwargs)
annotate(args - *kwargs)
Abstract base class

20. This query finds all entries between a start date of start_date and an end date of end_date.
when you add new apps to INSTALLED_APPS
get_or_create(**kwargs)
day
Entry.objects.filter(pub_date__range=(start_date - end_date))

21. Conjuntion operator for Q objects.
day
&
filter(**kwargs)
choices tuple

22. An iterable (e.g. - a list or tuple) of 2-tuples to use as options for this field. If this is given - Django's admin will use a select box instead of the standard text field and will limit options to those given.
choices
primary_key
|
delete()

23. These add custom "row-level" functionality to your objects. These act on a particular model instance.
ManyToManyField
Custom model methods
ForeignKey
reverse()

24. This query deletes all Entry objects with a pub_date year of 2005.
get_absolute_url()
Entry.objects.filter(pub_date__year=2005).delete()
month
save()

25. Takes the ouput of one filter and uses it as input for another filter. This works because a refinement of a QuerySet is itself a QuerySet.
class attributes
many-to-many relationship
filter chaining
Manager methods

26. Returns a dictionary of aggregate values (averages - sums - etc) calculated over the QuerySet. Each argument to this method specifies a value that will be included in the dictionary that is returned.
lt
Entry.objects.filter(id__gt=4)
aggregate(args - *kwargs)
exclude(**kwargs)

27. In this case - an intermediate model can have multiple foreign keys to the source model. Here - two foreign keys to the same model are permitted - but they will be treated as the two (different) sides of the many-to-many relation.
count()
Many-to-many relationship to self
istartswith
filter

28. If you are using this attribute on a ForeignKey or ManyToManyField - you must always specify a unique reverse name for the field.
year
related_name
Entry.objects.filter(pub_date__range=(start_date - end_date))
~

29. Negation operator for Q objects.
values(*fields)
&
~
contains

30. This object encapsulates a collection of keyword arguments - with the keys being field lookup types. These objects can be combined using the & and | operators - as well as negated with the ~ operator.
many-to-one relationship
Q()
iexact
gt

31. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.
relationship spanning
exclude(**kwargs)
unique
update()

32. A Python "magic method" that returns a unicode "representation" of any object.
pk
lt
__unicode__()
related_name

33. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
Entry.objects.filter(pub_date__year=2005).delete()
search
filter(**kwargs)
count()

34. If you pickle a QuerySet - this will force all the results to be loaded into memory prior to pickling. When you unpickle a QuerySet - it contains the results at the moment it was pickled - rather than the results that are currently in the database.
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
many-to-many relationship
Proxy model
pickling

35. This model type is useful if you only want to modify the Python-level behavior of a model - without changing the models fields in any way. This creates a stand-in for the original model. You can create - delete and update instances of this new model
Proxy model
isnull
filter
pk

36. A manager method which returns a single object. If there are no results that match the query - this method will raise a DoesNotExist exception. If more than one item matches this query - the method will raise MultipleObjectsReturned.
help_text
Entry.objects.filter(id__gt=4)
get(**kwargs)
iterator()

37. The default for this is the name of the child class followed by '_set'.
get_absolute_url()
Entry.objects.filter(pub_date__range=(start_date - end_date))
intermediate models
reverse name

38. This model method is used for updating a ManyToManyField.
relationship spanning
blank
Entry.objects.filter(id__gt=4)
add()

39. A Q object that encapsulates queries for entries with a question value that starts with 'What' in a case-insensitive fashion.

Warning: Invalid argument supplied for foreach() in /var/www/html/basicversity.com/show_quiz.php on line 183

40. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
Meta class
range
many-to-many relationship
ForeignKey

41. Lookup type that returns results with a case-insensitive end sequence.
primary_key
iendswith
in_bulk(id_list)
get(**kwargs)

42. This query finds all entries with an id greater than 4.
order_by(*fields)
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
Entry.objects.filter(id__gt=4)
aggregate(args - *kwargs)

43. This is a criterion that narrow down a QuerySet based on given parameters.
iexact
isnull
filter
iregex

44. Lookup type that returns results with a case-sensitive start sequence.
startswith
help_text
values(*fields)
Many-to-many relationship through an intermediate model

45. Performs an SQL update query for the specified fields - and returns the number of rows affected. This method is applied instantly and the only restriction on the QuerySet that is updated is that it can only update columns in the model's main table. F
defer(*fields)
|
values_list(*fields)
update(**kwargs)

46. Keyword shortcut for looking up an object by primary key.
values_list(*fields)
range
slicing
pk

47. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.
in
MultipleObjectsReturned
filter(**kwargs)
ordered

48. Returns the most recent object in the table - by date - using the field_name provided as the date field.
search
get_or_create(**kwargs)
clear() method
latest(field_name=None)

49. Fields are specified by these
choices tuple
choices
Entry.objects.filter(id__in=[1 - 3 - 4])
class attributes

50. Exception raised by get(**kwargs) if no items match the query.
using(alias)
reverse name
DoesNotExist
lt