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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. A convenience method for looking up an object with the given kwargs - creating one if necessary.
model
get_or_create(**kwargs)
Multi-table inheritance
delete()
2. This model method saves a model instance to the database. This method has no return value.
choices tuple
Meta class
|
save()
3. The database that will be used if this query is executed now
db
get_or_create(**kwargs)
through argument
startswith
4. This query deletes all Entry objects with a pub_date year of 2005.
select_related()
Entry.objects.filter(pub_date__year=2005).delete()
Many-to-many relationship through an intermediate model
Entry.objects.filter(id__gt=4)
5. This query finds all entries with an id greater than 4.
pk
get_absolute_url()
Entry.objects.filter(id__gt=4)
null
6. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
year
exact
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
latest(field_name=None)
7. 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
filter chaining
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
update()
8. Defined by a OneToOneField. You use it just like any other Field type: by including it as a class attribute of your model.
one-to-one relationship
blank
Q()
id field
9. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.
Entry.objects.filter(id__in=[1 - 3 - 4])
aggregate(args - *kwargs)
week_day
values(*fields)
10. Lookup type that returns results with a case-insensitive start sequence.
istartswith
Many-to-many relationship through an intermediate model
range
Entry.objects.filter(pub_date__range=(start_date - end_date))
11. 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.
Q(question__istartswith='What')
add()
all()
choices tuple
12. Lookup type that finds a case-sensitive regular expression match.
regex
Many-to-many relationship to self
order_by(*fields)
latest(field_name=None)
13. 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.
iexact
many-to-one relationship
get_absolute_url()
ManyToManyField
14. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
ordered
choices
isnull
create(**kwargs)
15. 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
Manager methods
reverse()
many-to-one relationship
select_related()
16. 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
values_list(*fields)
get_or_create(**kwargs)
reverse name
F()
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.
order_by(*fields)
when you add new apps to INSTALLED_APPS
reverse name
in_bulk(id_list)
18. Returns the most recent object in the table - by date - using the field_name provided as the date field.
get_or_create(**kwargs)
latest(field_name=None)
contains
unique
19. Lookup type that returns results with a case-sensitive end sequence.
day
endswith
Q()
when you add new apps to INSTALLED_APPS
20. Each one of these is a Python class that subclasses django.db.models.Model. Each attribute of one of these represents a database field.
model
iregex
choices tuple
Proxy model
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.
pickling
reverse()
choices
delete()
22. 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()
intermediate models
Many-to-many relationship through an intermediate model
iterator()
23. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
using(alias)
gt
distinct()
blank
24. 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.
help_text
reverse name
OneToOneField
create(**kwargs)
25. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
month
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
annotate(args - *kwargs)
day
26. This query finds all entries with an id in the list [1 - 3 - 4]
db
distinct()
Entry.objects.filter(id__in=[1 - 3 - 4])
filter
27. 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
Proxy model
order_by(*fields)
lt
Field lookups
28. If this option is True - the field is allowed to be blank. Default is False.
Entry.objects.filter(pub_date__year=2005).delete()
blank
lt
Entry.objects.filter(pub_date__range=(start_date - end_date))
29. If this option is True - Django will store empty values as NULL in the database. Default is False.
blank
filter(**kwargs)
range
null
30. Lookup type that returns results with a case-sensitive start sequence.
in
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
lt
startswith
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. If you are using this attribute on a ForeignKey or ManyToManyField - you must always specify a unique reverse name for the field.
defer(*fields)
related_name
many-to-one relationship
values(*fields)
33. 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
choices tuple
OneToOneField
choices
Abstract base class
34. A convenience method for constructing an object and saving it all in one step.
Many-to-many relationship through an intermediate model
month
create(**kwargs)
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
35. 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.
blank
update()
get(**kwargs)
relationship spanning
36. If True - this field is the primary key for the model.
intermediate models
primary_key
update(**kwargs)
QuerySet
37. 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
Many-to-many relationship through an intermediate model
exists()
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
Manager methods
38. 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
get(**kwargs)
evaluation
pk
class type
39. 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
Proxy model
filter chaining
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
all()
40. This field is added automatically - but this behavior can be overridden
gt
id field
iendswith
help_text
41. This gives your model metadata.
istartswith
when you add new apps to INSTALLED_APPS
Meta class
many-to-many relationship
42. 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
43. Lookup type that returns results that fall into an inclusive date range.
ordered
db
class type
range
44. 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
45. 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
F()
get_or_create(**kwargs)
annotate(args - *kwargs)
Manager
46. Defined by django.db.models.ForeignKey. You use it just like any other Field type: by including it as a class attribute of your model.
Restrictions on field names
id field
reverse name
many-to-one relationship
47. 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()
latest(field_name=None)
==
Manager methods
48. 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.
filter(**kwargs)
defer(*fields)
ForeignKey
update()
49. 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
select_related()
delete()
startswith
50. Fields are specified by these
class attributes
delete()
get(**kwargs)
in_bulk(id_list)