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Test your basic knowledge |
Django Queryset
Start Test
Study First
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. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
values(*fields)
all()
==
year
2. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.
default
startswith
exclude(**kwargs)
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
3. The database that will be used if this query is executed now
isnull
db
create(**kwargs)
iteration
4. Lookup type that yields a case-insensitive match.
iexact
ForeignKey
create(**kwargs)
Restrictions on field names
5. 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.
filter chaining
Proxy model
slicing
~
6. 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.
get_or_create(**kwargs)
ForeignKey
reverse()
contains
7. 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
help_text
lt
~
relationship spanning
8. 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
9. This field is added automatically - but this behavior can be overridden
id field
reverse()
search
save()
10. 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.
save()
contains
iteration
help_text
11. This represents a collection of objects from your database. It can have zero - one or many filters.
in_bulk(id_list)
regex
QuerySet
exclude(**kwargs)
12. 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)
Abstract base class
unique
choices
13. 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()
Meta class
evaluation
Manager methods
update(**kwargs)
14. 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
values(*fields)
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
Many-to-many relationship to self
select_related()
15. A convenience method for looking up an object with the given kwargs - creating one if necessary.
blank
iexact
get_or_create(**kwargs)
pk
16. 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.
Many-to-many relationship to self
add()
Entry.objects.filter(id__gt=4)
using(alias)
17. Takes a list of primary-key values and returns a dictionary mapping each primary-key value to an instance of the object with the given ID.
in_bulk(id_list)
Restrictions on field names
__unicode__()
&
18. 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.
iteration
OneToOneField
day
help_text
19. Lookup type for date/datetime fields that finds an exact day match.
day
in
latest(field_name=None)
count()
20. 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
Abstract base class
delete()
day
distinct()
21. 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.
intermediate models
Entry.objects.filter(pub_date__range=(start_date - end_date))
reverse()
isnull
22. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
db
month
lte
get(**kwargs)
23. 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.
reverse()
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
iendswith
Entry.objects.filter(pub_date__year=2005).delete()
24. Keyword shortcut for looking up an object by primary key.
pk
MultipleObjectsReturned
ForeignKey
order_by(*fields)
25. Lookup type that returns results greater than or equal to a given value.
Restrictions on field names
default
only(*fields)
gte
26. 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.
DoesNotExist
istartswith
exclude(**kwargs)
order_by(*fields)
27. 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
values_list(*fields)
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
Entry.objects.filter(pub_date__range=(start_date - end_date))
class type
28. Lookup type that returns results less than a given value.
lt
delete()
__unicode__()
contains
29. Used to get a QuerySet for a model. This is called 'objects' by default.
db
help_text
update(**kwargs)
Manager
30. Lookup type that returns results in a given list.
Many-to-many relationship through an intermediate model
in
latest(field_name=None)
null
31. 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()
Multi-table inheritance
distinct()
gte
32. Lookup type for date/datetime fields that finds a 'day of the week' match.
values(*fields)
Model metadata
week_day
Entry.objects.filter(id__gt=4)
33. (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.
startswith
values(*fields)
Multi-table inheritance
Restrictions on field names
34. This object encapsulates a collection of keyword arguments - with the keys being field lookup types. These objects can be combined using the & and | operators - as well as negated with the ~ operator.
Q()
ForeignKey
filter chaining
iteration
35. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
distinct()
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
gte
Field lookups
36. This query finds all entries between a start date of start_date and an end date of end_date.
values(*fields)
Entry.objects.filter(pub_date__range=(start_date - end_date))
Multi-table inheritance
exists()
37. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
values_list(*fields)
count()
filter(**kwargs)
slicing
38. Lookup type that returns results with a case-sensitive end sequence.
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
Entry.objects.filter(pub_date__range=(start_date - end_date))
endswith
Entry.objects.filter(pub_date__year=2005).delete()
39. Returns a new QuerySet containing objects that match the given lookup parameters.
iendswith
get_absolute_url()
Q()
filter(**kwargs)
40. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
filter
latest(field_name=None)
Field lookups
many-to-many relationship
41. Lookup type that tests for inclusion in a case-sensitive fashion.
lte
none()
contains
regex
42. a QuerySet can be sliced - using Python's array-slicing syntax.
regex
in_bulk(id_list)
slicing
class attributes
43. 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.
clear() method
add()
unique
Many-to-many relationship through an intermediate model
44. This tells Django how to calculate the URL for an object. Django uses this in its admin interface - and any time it needs to figure out a URL for an object.
get_absolute_url()
Entry.objects.filter(pub_date__year=2005).delete()
order_by(*fields)
one-to-one relationship
45. These methods are intended to do "table-wide" things.
endswith
Manager methods
filter(**kwargs)
iendswith
46. If True - this field is the primary key for the model.
primary_key
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
Proxy model
Custom model methods
47. 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
contains
lte
only(*fields)
evaluation
48. Can be used to remove all many-to-many relationships for an instance
filter
clear() method
exact
MultipleObjectsReturned
49. Lookup type that finds a case-sensitive regular expression match.
help_text
one-to-one relationship
regex
iteration
50. Lookup type that returns results with a case-insensitive end sequence.
Abstract base class
iendswith
Manager
==