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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. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
only(*fields)
distinct()
month
Proxy model
2. This model method saves a model instance to the database. This method has no return value.
pk
save()
F()
values_list(*fields)
3. If True - this field is the primary key for the model.
order_by(*fields)
==
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
primary_key
4. Lookup type that finds a case-insensitive regular expression match.
create(**kwargs)
Entry.objects.filter(id__in=[1 - 3 - 4])
iregex
pk
5. 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.
Many-to-many relationship to self
iterator()
ordered
Restrictions on field names
6. 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.
Manager
Abstract base class
reverse name
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
7. 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.
order_by(*fields)
filter
all()
annotate(args - *kwargs)
8. 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.
null
Many-to-many relationship through an intermediate model
iregex
count()
9. Exception raised by get(**kwargs) if more than one item matches the query.
slicing
MultipleObjectsReturned
Field lookups
one-to-one relationship
10. If this option is True - Django will store empty values as NULL in the database. Default is False.
iteration
iregex
Restrictions on field names
null
11. If this option is True - the field is allowed to be blank. Default is False.
all()
QuerySet
blank
pk
12. 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
all()
related_name
class type
Restrictions on field names
13. 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
14. (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.
iregex
iterator()
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
Restrictions on field names
15. 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.
filter(**kwargs)
iteration
update()
F()
16. This model method is used for updating a ManyToManyField.
add()
model
iregex
~
17. Lookup type that returns results with a case-insensitive end sequence.
Multi-table inheritance
iendswith
Field lookups
evaluation
18. 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.
many-to-one relationship
exists()
__unicode__()
Q(question__istartswith='What')
19. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
primary_key
year
all()
Meta class
20. These add custom "row-level" functionality to your objects. These act on a particular model instance.
range
Custom model methods
defer(*fields)
get(**kwargs)
21. This query finds all entries with an id in the list [1 - 3 - 4]
save()
ForeignKey
Entry.objects.filter(id__in=[1 - 3 - 4])
ordered
22. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
month
filter chaining
select_related()
Q(question__istartswith='What')
23. 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.
evaluation
exclude(**kwargs)
choices
Entry.objects.filter(id__in=[1 - 3 - 4])
24. Lookup type for date/datetime fields that finds a 'day of the week' match.
iteration
__unicode__()
week_day
Proxy model
25. 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
id field
exclude(**kwargs)
Entry.objects.filter(id__gt=4)
through argument
26. 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
evaluation
F()
month
exact
27. Lookup type that returns results greater than or equal to a given value.
get(**kwargs)
day
gte
evaluation
28. Lookup type that returns results with a case-sensitive start sequence.
startswith
get(**kwargs)
Custom model methods
add()
29. 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
30. Lookup type that returns results greater than a given value.
class type
gt
select_related()
year
31. The database that will be used if this query is executed now
class type
db
QuerySet
update(**kwargs)
32. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
choices
ManyToManyField
get_absolute_url()
many-to-many relationship
33. Fields are specified by these
&
iterator()
none()
class attributes
34. Disjunction operator for Q objects.
gt
DoesNotExist
|
in_bulk(id_list)
35. Negation operator for Q objects.
~
delete()
week_day
reverse name
36. 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.
__unicode__()
delete()
exact
in
37. restrictions on ________: (1) Your intermediate model must contain one - and only one - foreign key to the target model. (2) Your intermediate model must contain one - and only one - foreign key to the source model. (3) When defining a many-to-many r
all()
reverse()
intermediate models
latest(field_name=None)
38. Can be used to remove all many-to-many relationships for an instance
reverse name
only(*fields)
clear() method
in
39. A convenience method for constructing an object and saving it all in one step.
exclude(**kwargs)
create(**kwargs)
iteration
in_bulk(id_list)
40. This gives your model metadata.
model
Meta class
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
Q(question__istartswith='What')
41. 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.
default
ForeignKey
Multi-table inheritance
defer(*fields)
42. 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 to self
many-to-many relationship
none()
Manager
43. Lookup type that returns results less than or equal to a given value.
Abstract base class
many-to-many relationship
aggregate(args - *kwargs)
lte
44. Conjuntion operator for Q objects.
dates(field - kind - order='ASC')
annotate(args - *kwargs)
distinct()
&
45. 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.
==
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
reverse()
using(alias)
46. Returns the object matching the given lookup parameters
get(**kwargs)
intermediate models
get_or_create(**kwargs)
range
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
pickling
week_day
iterator()
get(**kwargs)
48. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
many-to-one relationship
Q()
count()
month
49. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
isnull
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
ForeignKey
Abstract base class
50. 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
Abstract base class
relationship spanning
slicing
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.