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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. 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.
default
QuerySet
update()
Multi-table inheritance
2. a QuerySet can be sliced - using Python's array-slicing syntax.
many-to-one relationship
slicing
filter(**kwargs)
range
3. Lookup type that returns results with a case-insensitive start sequence.
istartswith
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
pk
only(*fields)
4. 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()
help_text
values(*fields)
MultipleObjectsReturned
evaluation
5. 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()
filter
primary_key
one-to-one relationship
6. Lookup type that returns results in a given list.
gte
in
month
lte
7. If this option is True - Django will store empty values as NULL in the database. Default is False.
null
update()
iendswith
contains
8. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
MultipleObjectsReturned
isnull
Entry.objects.filter(id__in=[1 - 3 - 4])
contains
9. 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
10. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
search
count()
QuerySet
primary_key
11. 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
12. Returns the most recent object in the table - by date - using the field_name provided as the date field.
latest(field_name=None)
dates(field - kind - order='ASC')
clear() method
ManyToManyField
13. If True - the table does not permit duplicate values for this field.
latest(field_name=None)
unique
istartswith
one-to-one relationship
14. If you pickle a QuerySet - this will force all the results to be loaded into memory prior to pickling. When you unpickle a QuerySet - it contains the results at the moment it was pickled - rather than the results that are currently in the database.
annotate(args - *kwargs)
MultipleObjectsReturned
pickling
blank
15. Lookup type that returns results less than or equal to a given value.
regex
~
lte
model
16. 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
through argument
&
select_related()
slicing
17. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
class type
Field lookups
year
iregex
18. This represents a collection of objects from your database. It can have zero - one or many filters.
Model metadata
QuerySet
intermediate models
primary_key
19. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
create(**kwargs)
many-to-many relationship
order_by(*fields)
only(*fields)
20. This query finds all entries with an id greater than 4.
filter(**kwargs)
many-to-many relationship
Entry.objects.filter(id__gt=4)
MultipleObjectsReturned
21. These are "anything that's not a field" - such as ordering options (ordering) - database table name (db_table) - or human-readable singular and plural names (verbose_name and verbose_name_plural)
default
lt
Model metadata
through argument
22. 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.
month
through argument
exclude(**kwargs)
Many-to-many relationship to self
23. 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.
QuerySet
ManyToManyField
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
aggregate(args - *kwargs)
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.
OneToOneField
dates(field - kind - order='ASC')
get_or_create(**kwargs)
Manager
25. Lookup type that returns results with a case-insensitive end sequence.
iendswith
order_by(*fields)
choices
help_text
26. Exception raised by get(**kwargs) if more than one item matches the query.
filter
get_or_create(**kwargs)
MultipleObjectsReturned
many-to-many relationship
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
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
week_day
Proxy model
when you add new apps to INSTALLED_APPS
28. Negation operator for Q objects.
all()
filter(**kwargs)
~
through argument
29. This model method saves a model instance to the database. This method has no return value.
DoesNotExist
lt
regex
save()
30. 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
Restrictions on field names
Abstract base class
all()
search
31. 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()
Abstract base class
when you add new apps to INSTALLED_APPS
get(**kwargs)
32. This field is added automatically - but this behavior can be overridden
id field
help_text
Abstract base class
all()
33. Lookup type for date/datetime fields that finds an exact day match.
==
day
create(**kwargs)
week_day
34. Lookup type that returns results with a case-sensitive end sequence.
year
through argument
endswith
db
35. The default for this is the name of the child class followed by '_set'.
reverse name
help_text
Entry.objects.filter(id__gt=4)
get_absolute_url()
36. If this option is True - the field is allowed to be blank. Default is False.
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
iexact
blank
default
37. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
exclude(**kwargs)
QuerySet
range
==
38. In some complex data-modeling situations - your models might contain a lot of fields - some of which could contain a lot of data (for example - text fields) - or require expensive processing to convert them to Python objects. If you are using the res
regex
defer(*fields)
delete()
get(**kwargs)
39. A convenience method for constructing an object and saving it all in one step.
ordered
F()
create(**kwargs)
all()
40. 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.
search
filter(**kwargs)
order_by(*fields)
ManyToManyField
41. 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
evaluation
class type
==
update(**kwargs)
42. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.
ordered
gte
create(**kwargs)
iteration
43. 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
using(alias)
values(*fields)
clear() method
44. 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
lt
F()
Q()
get_absolute_url()
45. 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
46. Lookup type that tests for inclusion in a case-sensitive fashion.
when you add new apps to INSTALLED_APPS
contains
search
iregex
47. To activate your models
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
~
filter
none()
48. Can be used to remove all many-to-many relationships for an instance
get_or_create(**kwargs)
clear() method
id field
through argument
49. This model method is used for updating a ManyToManyField.
values_list(*fields)
add()
through argument
defer(*fields)
50. These methods are intended to do "table-wide" things.
Manager methods
when you add new apps to INSTALLED_APPS
regex
startswith