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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. Lookup type that returns results with a case-sensitive end sequence.
null
endswith
Restrictions on field names
istartswith

2. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
choices tuple
relationship spanning
distinct()
lt

3. 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()
ForeignKey
startswith
exists()

4. A Python "magic method" that returns a unicode "representation" of any object.
get(**kwargs)
only(*fields)
__unicode__()
class attributes

5. This model method is used for updating a ManyToManyField.
iterator()
add()
search
delete()

6. 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
exclude(**kwargs)
db
update(**kwargs)
none()

7. 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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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.
ManyToManyField
values(*fields)
count()
|

9. Disjunction operator for Q objects.
|
latest(field_name=None)
in_bulk(id_list)
Manager

10. A convenience method for constructing an object and saving it all in one step.
all()
add()
create(**kwargs)
ForeignKey

11. 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.
choices
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
week_day
defer(*fields)

12. 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
Q()
class type
Entry.objects.filter(id__gt=4)
when you add new apps to INSTALLED_APPS

13. This field is added automatically - but this behavior can be overridden
reverse()
endswith
id field
iexact

14. Negation operator for Q objects.
~
lt
Field lookups
choices

15. Lookup type that yields a case-insensitive match.
iterator()
exact
iexact
using(alias)

16. 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
aggregate(args - *kwargs)
filter(**kwargs)
Q(question__istartswith='What')
iterator()

17. 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
Manager methods
through argument
exclude(**kwargs)
ordered

18. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.
filter(**kwargs)
values(*fields)
|
primary_key

19. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.
regex
exclude(**kwargs)
Q()
lte

20. This query finds all entries with an id greater than 4.
only(*fields)
__unicode__()
Entry.objects.filter(id__gt=4)
ForeignKey

21. 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.
update()
Many-to-many relationship to self
filter
Entry.objects.filter(id__gt=4)

22. 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
all()
only(*fields)
ManyToManyField
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')

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.
exclude(**kwargs)
relationship spanning
default
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)

24. These methods are intended to do "table-wide" things.
contains
get_or_create(**kwargs)
Many-to-many relationship to self
Manager methods

25. The database that will be used if this query is executed now
db
exact
delete()
many-to-many relationship

26. (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.
endswith
Custom model methods
Restrictions on field names
Many-to-many relationship through an intermediate model

27. Exception raised by get(**kwargs) if no items match the query.
endswith
DoesNotExist
lte
all()

28. Lookup type that returns results with a case-sensitive start sequence.
startswith
values(*fields)
get_or_create(**kwargs)
lte

29. a QuerySet can be sliced - using Python's array-slicing syntax.
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
==
slicing
iexact

30. 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
unique
exists()
==

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.

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32. This gives your model metadata.
Meta class
Entry.objects.filter(pub_date__year=2005).delete()
Abstract base class
relationship spanning

33. Lookup type that finds a case-insensitive regular expression match.
iregex
gt
Meta class
model

34. If True - this field is the primary key for the model.
primary_key
Entry.objects.filter(id__in=[1 - 3 - 4])
~
==

35. A Q object that asks for entries with a question value that start with 'Who' or do not have a publication date of 2005.

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36. 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.
filter(**kwargs)
exact
reverse()
iendswith

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.
iterator()
in
get(**kwargs)
intermediate models

38. If True - the table does not permit duplicate values for this field.
unique
&
Q()
ordered

39. 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()
get(**kwargs)
Entry.objects.filter(pub_date__year=2005).delete()
evaluation
add()

40. Lookup type that returns results with a case-insensitive start sequence.
Q(question__istartswith='What')
istartswith
delete()
null

41. 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.
OneToOneField
update()
month
startswith

42. This is a criterion that narrow down a QuerySet based on given parameters.
filter
primary_key
filter(**kwargs)
Proxy model

43. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
class attributes
lt
order_by(*fields)
count()

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

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45. Fields are specified by these
blank
__unicode__()
class attributes
defer(*fields)

46. If this option is True - the field is allowed to be blank. Default is False.
blank
model
Model metadata
class type

47. 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
gt
Abstract base class
class attributes
Proxy model

48. 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
range
annotate(args - *kwargs)
Custom model methods

49. 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.
month
Abstract base class
filter chaining
Q()

50. Lookup type that returns results greater than a given value.
Abstract base class
gt
Custom model methods
filter