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Django Queryset

Subject : it-skills

Instructions:

Answer 50 questions in 15 minutes.
If you are not ready to take this test, you can study here.
Match each statement with the correct term.
Don't refresh. All questions and answers are randomly picked and ordered every time you load a test.

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. Lookup type that returns results with a case-insensitive start sequence.
exists()
Q()
istartswith
class type

2. This sets a field to a particular value for all the objects in a QuerySet. You can only set non-relation fields and ForeignKey fields using this method.
latest(field_name=None)
update()
MultipleObjectsReturned
choices

3. A Python "magic method" that returns a unicode "representation" of any object.
related_name
class type
__unicode__()
slicing

4. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.
delete()
filter(**kwargs)
id field
clear() method

5. Lookup type that returns results greater than or equal to a given value.
filter
gte
lte
reverse name

6. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
DoesNotExist
distinct()
id field
istartswith

7. Returns a copy of the current QuerySet (or QuerySet subclass you pass in). This can be useful in some situations where you might want to pass in either a model manager or a QuerySet and do further filtering on the result. You can safely call all() on
all()
create(**kwargs)
only(*fields)
ForeignKey

8. 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.
lt
delete()
values_list(*fields)
get_absolute_url()

9. 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.
QuerySet
istartswith
get(**kwargs)
update(**kwargs)

10. Returns an EmptyQuerySet -- a QuerySet that always evaluates to an empty list. This can be used in cases where you know that you should return an empty result set and your caller is expecting a QuerySet object (instead of returning an empty list - fo
Multi-table inheritance
filter
none()
when you add new apps to INSTALLED_APPS

11. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
==
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
exclude(**kwargs)
evaluation

12. Evaluates the QuerySet (by performing the query) and returns an iterator over the results. A QuerySet typically caches its results internally so that repeated evaluations do not result in additional queries; this method will instead read results dire
iterator()
slicing
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
iexact

13. This model method is used for updating a ManyToManyField.
evaluation
Many-to-many relationship to self
add()
OneToOneField

14. Lookup type that yields an "exact" match. If you don't provide a lookup type -- that is - if your keyword argument doesn't contain a double underscore -- the lookup type is assumed to be of this sort.
iregex
annotate(args - *kwargs)
create(**kwargs)
exact

15. 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 to self
Many-to-many relationship through an intermediate model
in
ManyToManyField

16. A convenience method for constructing an object and saving it all in one step.
choices
Q()
create(**kwargs)
DoesNotExist

17. If this option is True - Django will store empty values as NULL in the database. Default is False.
one-to-one relationship
delete()
db
null

18. Returns a DateQuerySet -- a QuerySet that evaluates to a list of datetime.datetime objects representing all available dates of a particular kind within the contents of the QuerySet.

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

19. These methods are intended to do "table-wide" things.
count()
Manager methods
Q(question__istartswith='What')
default

20. Lookup type that returns results in a given list.
range
in
gt
select_related()

21. In some complex data-modeling situations - your models might contain a lot of fields - some of which could contain a lot of data (for example - text fields) - or require expensive processing to convert them to Python objects. If you are using the res
defer(*fields)
many-to-many relationship
all()
iendswith

22. Returns the object matching the given lookup parameters
evaluation
annotate(args - *kwargs)
null
get(**kwargs)

23. Returns a QuerySet that will automatically "follow" foreign-key relationships - selecting that additional related-object data when it executes its query. This is a performance booster which results in (sometimes much) larger queries but means later u
Multi-table inheritance
select_related()
get_or_create(**kwargs)
contains

24. 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.
many-to-many relationship
order_by(*fields)
gte
all()

25. This is a criterion that narrow down a QuerySet based on given parameters.
pickling
&
filter
lt

26. If you are using this attribute on a ForeignKey or ManyToManyField - you must always specify a unique reverse name for the field.
related_name
relationship spanning
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
using(alias)

27. 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
update(**kwargs)
many-to-one relationship
in_bulk(id_list)
reverse name

28. Defined by a OneToOneField. You use it just like any other Field type: by including it as a class attribute of your model.
class type
filter
one-to-one relationship
Entry.objects.filter(pub_date__year=2005).delete()

29. This method is more or less the opposite of defer(). You call it with the fields that should not be deferred when retrieving a model. If you have a model where almost all the fields need to be deferred - using this method to specify the complementary
==
many-to-one relationship
order_by(*fields)
only(*fields)

30. A convenience method for looking up an object with the given kwargs - creating one if necessary.
Model metadata
Many-to-many relationship through an intermediate model
using(alias)
get_or_create(**kwargs)

31. 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.
Manager
choices
class attributes
default

32. These add custom "row-level" functionality to your objects. These act on a particular model instance.
Entry.objects.filter(pub_date__range=(start_date - end_date))
Many-to-many relationship to self
Custom model methods
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.

33. 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.
clear() method
relationship spanning
ordered
pickling

34. Lookup type that returns results less than a given value.
in
defer(*fields)
values_list(*fields)
lt

35. Here - you can't use add - create - or assignment (i.e. - beatles.members = [...]) to create relationships. You need to specify all the detail for the relationship required by the intermediate model.
ordered
Many-to-many relationship through an intermediate model
Entry.objects.filter(id__in=[1 - 3 - 4])
filter chaining

36. Defines a many-to-one relationship. ou use it just like any other Field type: by including it as a class attribute of your model.
filter(**kwargs)
ForeignKey
ManyToManyField
all()

37. A Q object that asks for entries with a question value that start with 'Who' or do not have a publication date of 2005.

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

38. Manager method used to retrieve every object in a model.
exclude(**kwargs)
all()
exists()
week_day

39. Lookup type that returns results that fall into an inclusive date range.
range
delete()
Restrictions on field names
class attributes

40. 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.
default
Many-to-many relationship to self
many-to-one relationship
related_name

41. Defined by django.db.models.ForeignKey. You use it just like any other Field type: by including it as a class attribute of your model.
many-to-one relationship
Multi-table inheritance
get_or_create(**kwargs)
slicing

42. Negation operator for Q objects.
~
blank
search
istartswith

43. 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
reverse()
unique
relationship spanning
==

44. Use this method to reverse the order in which a queryset's elements are returned. Calling this method a second time restores the ordering back to the normal direction.
contains
update(**kwargs)
Q()
reverse()

45. 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.
filter chaining
month
in_bulk(id_list)
Q()

46. 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.
__unicode__()
aggregate(args - *kwargs)
create(**kwargs)
Q()

47. This query finds all entries between a start date of start_date and an end date of end_date.
Many-to-many relationship through an intermediate model
get(**kwargs)
Entry.objects.filter(pub_date__range=(start_date - end_date))
id field

48. Lookup type that finds a case-sensitive regular expression match.
Q(question__istartswith='What')
Field lookups
regex
all()

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

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50. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
many-to-many relationship
exclude(**kwargs)
only(*fields)
update()