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Django Queryset

Subject : it-skills

Instructions:

Answer 50 questions in 15 minutes.
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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. 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
filter
create(**kwargs)
in
relationship spanning

2. Extra text to be displayed under the field on the object's admin form to provide assistance to users. It's useful for documentation even if your object doesn't have an admin form.
reverse()
help_text
count()
filter chaining

3. 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.
aggregate(args - *kwargs)
OneToOneField
many-to-one relationship
evaluation

4. If this option is True - Django will store empty values as NULL in the database. Default is False.
gt
get_or_create(**kwargs)
==
null

5. 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.
Many-to-many relationship to self
iterator()
exact
unique

6. 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
id field
primary_key
Q(question__istartswith='What')
iterator()

7. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
in_bulk(id_list)
annotate(args - *kwargs)
count()
Many-to-many relationship to self

8. Lookup type that finds a case-insensitive regular expression match.
exclude(**kwargs)
Entry.objects.filter(pub_date__range=(start_date - end_date))
lt
iregex

9. Adds to each object in the QuerySet with the provided list of aggregate values (averages - sums - etc) that have been computed over the objects that are related to the objects in the QuerySet. Each argument to this is content that will be added to ea
intermediate models
slicing
annotate(args - *kwargs)
relationship spanning

10. Used to get a QuerySet for a model. This is called 'objects' by default.
Manager
null
delete()
db

11. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
gte
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
==
choices

12. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.
exact
only(*fields)
ordered
aggregate(args - *kwargs)

13. 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.
MultipleObjectsReturned
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
order_by(*fields)
reverse()

14. 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
contains
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
update(**kwargs)
relationship spanning

15. Conjuntion operator for Q objects.
pickling
Q(question__istartswith='What')
F()
&

16. If this option is True - the field is allowed to be blank. Default is False.
blank
exclude(**kwargs)
OneToOneField
default

17. This query updates all the headlines with pub_date in 2007 to read 'Everything is the same'.

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

18. 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
Entry.objects.filter(id__gt=4)
only(*fields)
get(**kwargs)
endswith

19. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
filter chaining
model
filter(**kwargs)

20. Lookup type that tests for inclusion in a case-sensitive fashion.
model
contains
only(*fields)
filter(**kwargs)

21. Keyword shortcut for looking up an object by primary key.
values_list(*fields)
Many-to-many relationship through an intermediate model
pk
filter chaining

22. Lookup type for date/datetime fields that finds a 'day of the week' match.
when you add new apps to INSTALLED_APPS
all()
week_day
using(alias)

23. This query finds all entries with an id greater than 4.
relationship spanning
DoesNotExist
Entry.objects.filter(id__gt=4)
regex

24. Lookup type that returns results greater than or equal to a given value.
gte
Entry.objects.filter(id__in=[1 - 3 - 4])
ordered
when you add new apps to INSTALLED_APPS

25. Lookup type for date/datetime fields that finds an exact day match.
day
iteration
get_or_create(**kwargs)
Q(question__istartswith='What')

26. 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.
ManyToManyField
iregex
Q()
Q(question__startswith='Who') | ~Q(pub_date__year=2005)

27. 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
select_related()
add()
contains
only(*fields)

28. 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
startswith
unique
blank
Proxy model

29. A convenience method for constructing an object and saving it all in one step.
create(**kwargs)
OneToOneField
defer(*fields)
count()

30. This method is for controlling which database the QuerySet will be evaluated against if you are using more than one database. The only argument this method takes is the alias of a database - as defined in DATABASES.
filter(**kwargs)
select_related()
using(alias)
istartswith

31. 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

32. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.
values(*fields)
Many-to-many relationship to self
intermediate models
unique

33. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
endswith
DoesNotExist
distinct()
range

34. Takes a list of primary-key values and returns a dictionary mapping each primary-key value to an instance of the object with the given ID.
month
annotate(args - *kwargs)
in_bulk(id_list)
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.

35. Lookup type that returns results greater than a given value.
Proxy model
Entry.objects.filter(id__in=[1 - 3 - 4])
gt
ForeignKey

36. 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
annotate(args - *kwargs)
none()
ForeignKey
ordered

37. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
month
related_name
endswith
Q(question__startswith='Who') | ~Q(pub_date__year=2005)

38. 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

39. Lookup type that returns results less than or equal to a given value.
lte
istartswith
intermediate models
endswith

40. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
isnull
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
range
get(**kwargs)

41. 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.
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
ordered
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
aggregate(args - *kwargs)

42. A Python "magic method" that returns a unicode "representation" of any object.
Multi-table inheritance
using(alias)
__unicode__()
Entry.objects.filter(pub_date__range=(start_date - end_date))

43. 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.
Entry.objects.filter(id__in=[1 - 3 - 4])
istartswith
reverse()
year

44. Lookup type that returns results that fall into an inclusive date range.
endswith
Manager methods
range
clear() method

45. what the field _______ determines: (1) The database column type (e.g. INTEGER - VARCHAR); (2) The widget to use in Django's admin interface - if you care to use it (e.g. <input type="text"> - <select>); (3) The minimal validation requirements - used
relationship spanning
class type
aggregate(args - *kwargs)
many-to-one relationship

46. 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.
class type
get_absolute_url()
Model metadata
Q()

47. Lookup type that returns results with a case-sensitive end sequence.
==
endswith
Proxy model
delete()

48. These are "anything that's not a field" - such as ordering options (ordering) - database table name (db_table) - or human-readable singular and plural names (verbose_name and verbose_name_plural)
Model metadata
annotate(args - *kwargs)
ForeignKey
week_day

49. A convenience method for looking up an object with the given kwargs - creating one if necessary.
Entry.objects.filter(id__in=[1 - 3 - 4])
get_or_create(**kwargs)
null
filter(**kwargs)

50. Lookup type that returns results with a case-insensitive start sequence.
~
istartswith
in
filter(**kwargs)