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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. 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
gt
|
Abstract base class
day
2. 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.
clear() method
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
related_name
aggregate(args - *kwargs)
3. Lookup type that corresponds to a boolean full-text search - taking advantage of full-text indexing. This is like contains but is significantly faster due to full-text indexing.
defer(*fields)
pk
search
Entry.objects.filter(pub_date__range=(start_date - end_date))
4. Lookup type that returns results that fall into an inclusive date range.
range
default
get(**kwargs)
clear() method
5. 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
get_or_create(**kwargs)
clear() method
model
6. This method immediately deletes the object and has no return value.
id field
gt
latest(field_name=None)
delete()
7. Lookup type that returns results with a case-insensitive end sequence.
values_list(*fields)
none()
iendswith
unique
8. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
intermediate models
reverse name
isnull
Q()
9. Returns a dictionary of aggregate values (averages - sums - etc) calculated over the QuerySet. Each argument to this method specifies a value that will be included in the dictionary that is returned.
aggregate(args - *kwargs)
intermediate models
istartswith
evaluation
10. Exception raised by get(**kwargs) if no items match the query.
~
endswith
only(*fields)
DoesNotExist
11. Fields are specified by these
class attributes
defer(*fields)
get(**kwargs)
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
12. 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
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
week_day
iterator()
istartswith
filter
14. This model method is used for updating a ManyToManyField.
add()
class attributes
lte
gte
15. 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()
range
exact
related_name
16. 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()
latest(field_name=None)
F()
count()
17. This query uses an F object to increment the pingback count for every entry in the blog.
Warning
: Invalid argument supplied for foreach() in
/var/www/html/basicversity.com/show_quiz.php
on line
183
18. 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.
lt
get(**kwargs)
Entry.objects.filter(pub_date__range=(start_date - end_date))
choices
19. 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
select_related()
delete()
ordered
aggregate(args - *kwargs)
20. 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
in
year
only(*fields)
iregex
21. 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()
Manager
values_list(*fields)
istartswith
22. Lookup type that returns results less than a given value.
choices
db
distinct()
lt
23. 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.
OneToOneField
Entry.objects.filter(pub_date__range=(start_date - end_date))
evaluation
iexact
24. 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
endswith
through argument
Q(question__istartswith='What')
update(**kwargs)
25. Lookup type that yields a case-insensitive match.
exists()
through argument
exclude(**kwargs)
iexact
26. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
Many-to-many relationship through an intermediate model
regex
==
values(*fields)
27. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
in
Proxy model
many-to-many relationship
add()
28. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
count()
month
default
unique
29. Returns the most recent object in the table - by date - using the field_name provided as the date field.
iexact
isnull
latest(field_name=None)
ordered
30. The database that will be used if this query is executed now
many-to-one relationship
contains
db
istartswith
31. These add custom "row-level" functionality to your objects. These act on a particular model instance.
get_absolute_url()
QuerySet
gt
Custom model methods
32. If True - this field is the primary key for the model.
primary_key
choices
Entry.objects.filter(pub_date__range=(start_date - end_date))
Entry.objects.filter(pub_date__year=2005).delete()
33. Exception raised by get(**kwargs) if more than one item matches the query.
MultipleObjectsReturned
reverse()
Abstract base class
help_text
34. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
Multi-table inheritance
istartswith
save()
month
35. This represents a collection of objects from your database. It can have zero - one or many filters.
values(*fields)
QuerySet
class type
filter
36. This is a criterion that narrow down a QuerySet based on given parameters.
filter
save()
Entry.objects.filter(id__in=[1 - 3 - 4])
Q(question__istartswith='What')
37. Returns the object matching the given lookup parameters
get(**kwargs)
lte
F()
DoesNotExist
38. 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
relationship spanning
null
Meta class
&
39. 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.
Q()
get(**kwargs)
range
Multi-table inheritance
40. 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.
filter
help_text
day
endswith
41. A convenience method for constructing an object and saving it all in one step.
range
create(**kwargs)
through argument
all()
42. This gives your model metadata.
Q()
gte
F()
Meta class
43. If this option is True - Django will store empty values as NULL in the database. Default is False.
null
DoesNotExist
iexact
lte
44. 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
45. A QuerySet is iterable - and it executes its database query the first time you iterate over it.
exclude(**kwargs)
Field lookups
iteration
regex
46. (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.
one-to-one relationship
get(**kwargs)
Restrictions on field names
unique
47. 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.
reverse name
choices tuple
ordered
update()
48. This query finds all entries with an id in the list [1 - 3 - 4]
when you add new apps to INSTALLED_APPS
Entry.objects.filter(id__in=[1 - 3 - 4])
class type
ManyToManyField
49. This model method saves a model instance to the database. This method has no return value.
save()
values(*fields)
startswith
when you add new apps to INSTALLED_APPS
50. 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()
ForeignKey
null
create(**kwargs)