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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. 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
none()
Entry.objects.filter(id__gt=4)
using(alias)
get(**kwargs)

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.
update()
many-to-one relationship
&
Entry.objects.filter(pub_date__range=(start_date - end_date))

3. Lookup type that returns results in a given list.
iexact
when you add new apps to INSTALLED_APPS
&
in

4. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
pk
evaluation
save()
isnull

5. 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.
gt
reverse name
filter chaining
values_list(*fields)

6. If this option is True - the field is allowed to be blank. Default is False.
lte
primary_key
values_list(*fields)
blank

7. Returns a new QuerySet containing objects that match the given lookup parameters.
Q()
update()
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
filter(**kwargs)

8. 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.
ordered
relationship spanning
ManyToManyField
add()

9. Returns the object matching the given lookup parameters
using(alias)
contains
get(**kwargs)
class type

10. A Python "magic method" that returns a unicode "representation" of any object.
__unicode__()
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
Many-to-many relationship to self
values(*fields)

11. This query deletes all Entry objects with a pub_date year of 2005.
Entry.objects.filter(pub_date__year=2005).delete()
contains
__unicode__()
all()

12. 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.
all()
only(*fields)
ForeignKey
Many-to-many relationship to self

13. Lookup type that returns results with a case-insensitive end sequence.
reverse name
many-to-many relationship
dates(field - kind - order='ASC')
iendswith

14. 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.
Many-to-many relationship through an intermediate model
startswith
ForeignKey
&

15. A convenience method for looking up an object with the given kwargs - creating one if necessary.
get_or_create(**kwargs)
iexact
ManyToManyField
through argument

16. 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
ManyToManyField
defer(*fields)
Restrictions on field names
many-to-one relationship

17. Lookup type that finds a case-sensitive regular expression match.
db
regex
Manager
update()

18. This method immediately deletes the object and has no return value.
delete()
gte
get_or_create(**kwargs)
istartswith

19. If True - the table does not permit duplicate values for this field.
create(**kwargs)
using(alias)
week_day
unique

20. Returns True if the QuerySet contains any results - and False if not. This tries to perform the query in the simplest and fastest way possible - but it does execute nearly the same query. This means that calling this method on a queryset is faster th
related_name
exists()
gt
regex

21. Lookup type for date/datetime fields that finds a 'day of the week' match.
week_day
Field lookups
choices tuple
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.

22. Lookup type that returns results with a case-insensitive start sequence.
slicing
model
istartswith
get(**kwargs)

23. Used to get a QuerySet for a model. This is called 'objects' by default.
select_related()
Manager
null
Proxy model

24. 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.
Entry.objects.filter(pub_date__year=2005).delete()
filter chaining
add()
in_bulk(id_list)

25. When to run syncdb
search
when you add new apps to INSTALLED_APPS
Proxy model
OneToOneField

26. This represents a collection of objects from your database. It can have zero - one or many filters.
reverse name
QuerySet
exclude(**kwargs)
many-to-one relationship

27. (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.
Restrictions on field names
lte
in_bulk(id_list)
filter

28. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
get(**kwargs)
distinct()
values(*fields)
Q(question__startswith='Who') | ~Q(pub_date__year=2005)

29. Fields are specified by these
class attributes
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
select_related()
Many-to-many relationship to self

30. This model method saves a model instance to the database. This method has no return value.
contains
aggregate(args - *kwargs)
save()
in

31. 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

32. 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.
reverse()
QuerySet
get_or_create(**kwargs)
lt

33. To activate your models
when you add new apps to INSTALLED_APPS
none()
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.

34. Lookup type for date/datetime fields that finds an exact day match.
one-to-one relationship
day
endswith
Custom model methods

35. The database that will be used if this query is executed now
db
filter
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
create(**kwargs)

36. A convenience method for constructing an object and saving it all in one step.
related_name
create(**kwargs)
save()
contains

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

38. 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

39. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.
values(*fields)
clear() method
Field lookups
Entry.objects.filter(id__in=[1 - 3 - 4])

40. Lookup type that returns results greater than or equal to a given value.
Restrictions on field names
gte
related_name
&

41. Keyword shortcut for looking up an object by primary key.
related_name
get_or_create(**kwargs)
pk
one-to-one relationship

42. 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.
istartswith
Many-to-many relationship to self
lte
order_by(*fields)

43. If True - this field is the primary key for the model.
Entry.objects.filter(pub_date__year=2005).delete()
primary_key
latest(field_name=None)
pickling

44. Lookup type that returns results less than a given value.
lt
class type
in
help_text

45. 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
year
lt
intermediate models
all()

46. 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
Custom model methods
intermediate models
add()
gte

47. This field is added automatically - but this behavior can be overridden
id field
startswith
Entry.objects.filter(pub_date__range=(start_date - end_date))
evaluation

48. 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
MultipleObjectsReturned
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
pickling
iterator()

49. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
reverse name
month
Manager
pickling

50. 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
endswith
using(alias)
unique