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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. If this option is True - the field is allowed to be blank. Default is False.
Entry.objects.filter(id__in=[1 - 3 - 4])
relationship spanning
Entry.objects.filter(pub_date__year=2005).delete()
blank

2. This object allows you to compare the value of a model field with another field on the same model. Django supports the use of addition - subtraction - multiplication - division and modulo arithmetic with these objects - both with constants and with o
F()
delete()
order_by(*fields)
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)

3. 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.
choices tuple
day
Many-to-many relationship through an intermediate model
pickling

4. Lookup type that returns results with a case-sensitive end sequence.
delete()
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
endswith
lt

5. A Python "magic method" that returns a unicode "representation" of any object.
Field lookups
relationship spanning
__unicode__()
exclude(**kwargs)

6. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
Proxy model
month
Model metadata
ordered

7. Fields are specified by these
class attributes
many-to-one relationship
iexact
none()

8. 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
only(*fields)
using(alias)
update(**kwargs)
help_text

9. Returns a new QuerySet containing objects that match the given lookup parameters.
endswith
filter(**kwargs)
year
dates(field - kind - order='ASC')

10. Lookup type that returns results with a case-insensitive end sequence.
Many-to-many relationship through an intermediate model
none()
select_related()
iendswith

11. These add custom "row-level" functionality to your objects. These act on a particular model instance.
Abstract base class
slicing
Custom model methods
Restrictions on field names

12. This query finds all entries with an id greater than 4.
day
gt
Entry.objects.filter(id__gt=4)
filter(**kwargs)

13. This query deletes all Entry objects with a pub_date year of 2005.
class attributes
reverse name
many-to-one relationship
Entry.objects.filter(pub_date__year=2005).delete()

14. 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
class type
using(alias)
regex
MultipleObjectsReturned

15. Used to get a QuerySet for a model. This is called 'objects' by default.
Manager
Proxy model
pickling
gt

16. Disjunction operator for Q objects.
Q()
|
create(**kwargs)
pickling

17. Lookup type that returns results that fall into an inclusive date range.
iexact
range
through argument
update(**kwargs)

18. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
count()
Manager
create(**kwargs)
|

19. Keyword shortcut for looking up an object by primary key.
pk
Restrictions on field names
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
endswith

20. Defined by a OneToOneField. You use it just like any other Field type: by including it as a class attribute of your model.
save()
exclude(**kwargs)
Manager methods
one-to-one relationship

21. 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.
exact
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
delete()
filter(**kwargs)

22. Exception raised by get(**kwargs) if no items match the query.
choices
DoesNotExist
create(**kwargs)
get_or_create(**kwargs)

23. 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.
ordered
Q()
default
when you add new apps to INSTALLED_APPS

24. 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.
ForeignKey
lt
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
values(*fields)

25. If you are using this attribute on a ForeignKey or ManyToManyField - you must always specify a unique reverse name for the field.
related_name
range
pk
istartswith

26. The default for this is the name of the child class followed by '_set'.
using(alias)
reverse name
search
filter(**kwargs)

27. Lookup type that returns results with a case-insensitive start sequence.
regex
istartswith
pickling
Many-to-many relationship to self

28. 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.
exclude(**kwargs)
using(alias)
create(**kwargs)
Entry.objects.filter(id__gt=4)

29. Negation operator for Q objects.
Many-to-many relationship to self
none()
~
all()

30. Lookup type that returns results greater than a given value.
id field
many-to-many relationship
gt
Meta class

31. Manager method used to retrieve every object in a model.
all()
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
Meta class
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)

32. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.
filter(**kwargs)
ordered
Restrictions on field names
==

33. 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

34. 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.
exists()
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
Many-to-many relationship through an intermediate model
iexact

35. 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
null
__unicode__()
day

36. 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()
related_name
help_text
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)

37. 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
get(**kwargs)
exact
Proxy model
gt

38. 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.
create(**kwargs)
iterator()
iteration
Multi-table inheritance

39. Returns the object matching the given lookup parameters
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
many-to-many relationship
all()
get(**kwargs)

40. Returns the most recent object in the table - by date - using the field_name provided as the date field.
day
latest(field_name=None)
Q(question__istartswith='What')
select_related()

41. 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
get_absolute_url()
choices tuple
add()
annotate(args - *kwargs)

42. 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

43. A convenience method for looking up an object with the given kwargs - creating one if necessary.
slicing
OneToOneField
get_or_create(**kwargs)
regex

44. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
lte
DoesNotExist
year
get_or_create(**kwargs)

45. Lookup type for date/datetime fields that finds an exact day match.
|
dates(field - kind - order='ASC')
day
filter chaining

46. 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()
default
none()
Manager

47. 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.
QuerySet
month
Many-to-many relationship to self
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)

48. 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
many-to-many relationship
blank
none()
related_name

49. 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.
Restrictions on field names
slicing
order_by(*fields)
create(**kwargs)

50. The database that will be used if this query is executed now
defer(*fields)
exact
&
db