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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. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.
ordered
F()
filter(**kwargs)
istartswith

2. The database that will be used if this query is executed now
db
reverse()
Q()
pk

3. Performs an SQL delete query on all rows in the QuerySet. This method is applied instantly. You cannot call this method on a QuerySet that has had a slice taken or can otherwise no longer be filtered.
startswith
get(**kwargs)
ForeignKey
delete()

4. A convenience method for constructing an object and saving it all in one step.
pk
annotate(args - *kwargs)
exclude(**kwargs)
create(**kwargs)

5. Returns a new QuerySet containing objects that match the given lookup parameters.
Entry.objects.filter(pub_date__range=(start_date - end_date))
iregex
filter(**kwargs)
db

6. If this option is True - the field is allowed to be blank. Default is False.
exists()
save()
lte
blank

7. A convenience method for looking up an object with the given kwargs - creating one if necessary.
get_or_create(**kwargs)
istartswith
unique
reverse()

8. This model method saves a model instance to the database. This method has no return value.
values_list(*fields)
delete()
|
save()

9. 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
OneToOneField
none()
unique
get_absolute_url()

10. a QuerySet can be sliced - using Python's array-slicing syntax.
slicing
aggregate(args - *kwargs)
month
ForeignKey

11. Lookup type that finds a case-insensitive regular expression match.
iregex
Abstract base class
aggregate(args - *kwargs)
none()

12. 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
range
choices tuple
annotate(args - *kwargs)
~

13. 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
update()
iterator()
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
==

14. 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.
lt
|
delete()
ManyToManyField

15. Evaluation happens upon use the "step" parameter of slice syntax - the first time you iterate over it - when pickling or caching results - upon calling repr() - upon calling len() - upon calling list() - upon calling bool()
evaluation
default
iterator()
values(*fields)

16. 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.
help_text
aggregate(args - *kwargs)
delete()
Entry.objects.filter(id__in=[1 - 3 - 4])

17. 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.
count()
reverse()
exact
iendswith

18. Lookup type that finds a case-sensitive regular expression match.
regex
ForeignKey
DoesNotExist
isnull

19. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
month
reverse()
many-to-many relationship
slicing

20. Lookup type that returns results in a given list.
ForeignKey
in
iregex
Entry.objects.filter(pub_date__year=2005).delete()

21. 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.
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
values_list(*fields)
DoesNotExist
search

22. This is a criterion that narrow down a QuerySet based on given parameters.
exists()
filter
search
Entry.objects.filter(pub_date__year=2005).delete()

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
exact
save()
ForeignKey
select_related()

24. 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
using(alias)
get(**kwargs)
Proxy model
Field lookups

25. These add custom "row-level" functionality to your objects. These act on a particular model instance.
intermediate models
Entry.objects.filter(id__gt=4)
filter(**kwargs)
Custom model methods

26. This class type is useful when you just want to use the parent class to hold information that you don't want to have to type out for each child model. This class isn't going to ever be used in isolation. When it is used as a base class for other mode
istartswith
Abstract base class
values_list(*fields)
get_absolute_url()

27. This gives your model metadata.
Meta class
intermediate models
week_day
save()

28. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.
aggregate(args - *kwargs)
choices tuple
get_absolute_url()
filter(**kwargs)

29. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
distinct()
MultipleObjectsReturned
isnull
lte

30. 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.
get(**kwargs)
reverse name
istartswith
filter(**kwargs)

31. 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)
Q(question__istartswith='What')
class attributes
ordered

32. 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
DoesNotExist
iregex
istartswith

33. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
slicing
filter(**kwargs)
count()
dates(field - kind - order='ASC')

34. 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.
week_day
create(**kwargs)
Multi-table inheritance
select_related()

35. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
==
Manager
aggregate(args - *kwargs)
endswith

36. 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

37. 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.
model
many-to-one relationship
Entry.objects.filter(id__gt=4)
choices

38. 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
model
iterator()

39. If you are using this attribute on a ForeignKey or ManyToManyField - you must always specify a unique reverse name for the field.
filter chaining
all()
related_name
__unicode__()

40. 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.
pickling
slicing
filter(**kwargs)
annotate(args - *kwargs)

41. A Python "magic method" that returns a unicode "representation" of any object.
Manager
filter(**kwargs)
contains
__unicode__()

42. (1) These cannot be Python reserved words - because that would result in a Python syntax error. (2) These cannot contain more than one underscore in a row - due to the way Django's query lookup syntax works.
delete()
exclude(**kwargs)
Restrictions on field names
only(*fields)

43. Lookup type that returns results with a case-sensitive end sequence.
Model metadata
model
endswith
unique

44. Can be used to remove all many-to-many relationships for an instance
clear() method
default
MultipleObjectsReturned
select_related()

45. Returns the object matching the given lookup parameters
reverse()
get(**kwargs)
filter
ForeignKey

46. Lookup type that returns results less than a given value.
Multi-table inheritance
exists()
model
lt

47. 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
blank
pk
intermediate models
|

48. Lookup type that returns results with a case-sensitive start sequence.
startswith
Entry.objects.filter(id__gt=4)
Many-to-many relationship through an intermediate model
Manager

49. 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

50. This model method is used for updating a ManyToManyField.
Q()
Entry.objects.filter(id__in=[1 - 3 - 4])
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
add()