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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. This method immediately deletes the object and has no return value.
delete()
range
Model metadata
Entry.objects.filter(pub_date__year=2005).delete()

2. This style of inheritanc is useful when you're subclassing an existing model (perhaps something from another application entirely) and want each model to have its own database table. Here - each model in the hierarchy is a model all by itself.
DoesNotExist
Multi-table inheritance
filter(**kwargs)
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)

3. Keyword shortcut for looking up an object by primary key.
~
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
exists()
pk

4. 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
iendswith
none()
lte
default

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.
startswith
db
Proxy model
Many-to-many relationship to self

6. Disjunction operator for Q objects.
|
OneToOneField
isnull
related_name

7. 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.
one-to-one relationship
select_related()
choices
choices tuple

8. Lookup type that returns results greater than a given value.
filter(**kwargs)
iterator()
through argument
gt

9. Lookup type that finds a case-insensitive regular expression match.
iregex
startswith
aggregate(args - *kwargs)
ForeignKey

10. Lookup type that tests for inclusion in a case-sensitive fashion.
when you add new apps to INSTALLED_APPS
contains
Proxy model
filter(**kwargs)

11. Lookup type that returns results with a case-sensitive start sequence.
reverse name
exclude(**kwargs)
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
startswith

12. Lookup type that yields a case-insensitive match.
reverse()
Manager methods
==
iexact

13. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.
iendswith
create(**kwargs)
filter(**kwargs)
pickling

14. 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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15. A convenience method for looking up an object with the given kwargs - creating one if necessary.
get_or_create(**kwargs)
evaluation
latest(field_name=None)
contains

16. 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.
related_name
values(*fields)
order_by(*fields)
none()

17. Lookup type that returns results with a case-insensitive end sequence.
filter
DoesNotExist
iendswith
Q(question__startswith='Who') | ~Q(pub_date__year=2005)

18. This model method is used for updating a ManyToManyField.
db
choices
add()
isnull

19. Lookup type that returns results greater than or equal to a given value.
gte
Model metadata
week_day
get(**kwargs)

20. This method returns tuples of values when iterated over. Each tuple contains the value from the respective field passed into the call to this method -- so the first item is the first field - etc.
ordered
values_list(*fields)
count()
filter

21. This query deletes all Entry objects with a pub_date year of 2005.
get_or_create(**kwargs)
Entry.objects.filter(pub_date__year=2005).delete()
Proxy model
__unicode__()

22. Defines a one-to-one relationship. You use it just like any other Field type: by including it as a class attribute of your model.
OneToOneField
save()
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
all()

23. Lookup type that returns results with a case-sensitive end sequence.
~
endswith
pickling
order_by(*fields)

24. These methods are intended to do "table-wide" things.
intermediate models
Q()
in_bulk(id_list)
Manager methods

25. Lookup type for date/datetime fields that finds an exact day match.
range
day
get(**kwargs)
iteration

26. This is a criterion that narrow down a QuerySet based on given parameters.
Proxy model
month
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
filter

27. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
isnull
many-to-many relationship
one-to-one relationship
filter(**kwargs)

28. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
update()
model
values(*fields)
isnull

29. If you are using this attribute on a ForeignKey or ManyToManyField - you must always specify a unique reverse name for the field.
year
create(**kwargs)
iexact
related_name

30. Sometimes - the Django query syntax by itself can't easily express a complex WHERE clause. For these edge cases - Django provides this QuerySet modifier -- a hook for injecting specific clauses into the SQL generated by a QuerySet.
Custom model methods
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
update()
slicing

31. Lookup type that returns results less than a given value.
F()
filter(**kwargs)
lt
|

32. restrictions on ________: (1) Your intermediate model must contain one - and only one - foreign key to the target model. (2) Your intermediate model must contain one - and only one - foreign key to the source model. (3) When defining a many-to-many r
intermediate models
endswith
Entry.objects.filter(pub_date__year=2005).delete()
Entry.objects.filter(id__in=[1 - 3 - 4])

33. Manager method used to retrieve every object in a model.
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
default
get_or_create(**kwargs)
all()

34. This query finds all entries between a start date of start_date and an end date of end_date.
Entry.objects.filter(pub_date__range=(start_date - end_date))
Manager
unique
month

35. A QuerySet is iterable - and it executes its database query the first time you iterate over it.
Entry.objects.filter(id__gt=4)
range
iteration
primary_key

36. The value given in the absence of a specified value for the field. This can be a value or a callable object. If callable it will be called every time a new object is created.
default
delete()
iexact
MultipleObjectsReturned

37. 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.
Custom model methods
get(**kwargs)
Restrictions on field names
filter

38. Fields are specified by these
Model metadata
lt
all()
class attributes

39. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
year
Q(question__istartswith='What')
relationship spanning
==

40. 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.
MultipleObjectsReturned
gt
help_text
order_by(*fields)

41. Lookup type for date/datetime fields that finds a 'day of the week' match.
week_day
Entry.objects.filter(id__gt=4)
one-to-one relationship
order_by(*fields)

42. Lookup type that returns results that fall into an inclusive date range.
Restrictions on field names
lte
range
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.

43. To activate your models
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
update()
order_by(*fields)
MultipleObjectsReturned

44. These add custom "row-level" functionality to your objects. These act on a particular model instance.
reverse()
iregex
Custom model methods
select_related()

45. 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
get(**kwargs)
relationship spanning
primary_key
Multi-table inheritance

46. Specifies the model that will be used to govern the many-to-many relationship. You can then put extra fields on the intermediate model. The intermediate model is associated with the ManyToManyField using this to point to the model that will act as an
through argument
order_by(*fields)
lte
null

47. 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.
Many-to-many relationship through an intermediate model
Entry.objects.filter(pub_date__year=2005).delete()
Q(question__istartswith='What')
lt

48. This query finds all entries with an id greater than 4.
select_related()
null
Manager methods
Entry.objects.filter(id__gt=4)

49. 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
model
Proxy model
delete()
using(alias)

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

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