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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.
get_or_create(**kwargs)
delete()
defer(*fields)
Custom model methods
2. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
choices
count()
ordered
values_list(*fields)
3. This method immediately deletes the object and has no return value.
__unicode__()
evaluation
delete()
save()
4. This method returns tuples of values when iterated over. Each tuple contains the value from the respective field passed into the call to this method -- so the first item is the first field - etc.
values_list(*fields)
lte
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
slicing
5. Fields are specified by these
class attributes
lte
exists()
istartswith
6. This is a criterion that narrow down a QuerySet based on given parameters.
Proxy model
evaluation
null
filter
7. Used to get a QuerySet for a model. This is called 'objects' by default.
help_text
Manager
iendswith
contains
8. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
Many-to-many relationship through an intermediate model
year
model
lt
9. 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
search
defer(*fields)
lte
pk
10. This represents a collection of objects from your database. It can have zero - one or many filters.
select_related()
QuerySet
endswith
pk
11. 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.
help_text
when you add new apps to INSTALLED_APPS
F()
model
12. 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.
db
day
using(alias)
class attributes
13. 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.
QuerySet
search
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
model
14. Exception raised by get(**kwargs) if more than one item matches the query.
MultipleObjectsReturned
id field
Q(question__istartswith='What')
iexact
15. This model method is used for updating a ManyToManyField.
add()
values(*fields)
istartswith
values_list(*fields)
16. 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
iexact
relationship spanning
istartswith
ForeignKey
17. If True - this field is the primary key for the model.
ForeignKey
primary_key
count()
|
18. Manager method used to retrieve every object in a model.
year
all()
ordered
in_bulk(id_list)
19. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
clear() method
ordered
unique
20. 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.
class type
db
lt
Many-to-many relationship to self
21. 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.
many-to-one relationship
pickling
day
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
22. 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
contains
year
Abstract base class
select_related()
23. This field is added automatically - but this behavior can be overridden
delete()
ForeignKey
relationship spanning
id field
24. A Python "magic method" that returns a unicode "representation" of any object.
values(*fields)
model
__unicode__()
get(**kwargs)
25. 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.
none()
evaluation
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
in_bulk(id_list)
26. a QuerySet can be sliced - using Python's array-slicing syntax.
Field lookups
get(**kwargs)
gte
slicing
27. To activate your models
contains
Multi-table inheritance
iregex
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
28. Can be used to remove all many-to-many relationships for an instance
clear() method
search
db
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
29. This query finds all entries with an id in the list [1 - 3 - 4]
lt
Entry.objects.filter(id__in=[1 - 3 - 4])
endswith
month
30. Each one of these is a Python class that subclasses django.db.models.Model. Each attribute of one of these represents a database field.
choices tuple
update(**kwargs)
many-to-many relationship
model
31. 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
32. 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.
__unicode__()
none()
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
choices tuple
33. If this option is True - Django will store empty values as NULL in the database. Default is False.
lt
choices
null
using(alias)
34. Lookup type that returns results with a case-sensitive end sequence.
Manager methods
Meta class
endswith
MultipleObjectsReturned
35. 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(id__in=[1 - 3 - 4])
Proxy model
Meta class
delete()
36. Disjunction operator for Q objects.
iregex
|
Q()
order_by(*fields)
37. Returns a new QuerySet containing objects that match the given lookup parameters.
filter(**kwargs)
Proxy model
help_text
all()
38. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
all()
range
month
get_or_create(**kwargs)
39. 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
related_name
filter
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
40. 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
41. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.
relationship spanning
values(*fields)
update()
get_absolute_url()
42. If this option is True - the field is allowed to be blank. Default is False.
relationship spanning
__unicode__()
blank
using(alias)
43. 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()
save()
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
update(**kwargs)
44. 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
Restrictions on field names
istartswith
gt
through argument
45. 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
id field
all()
day
QuerySet
46. Lookup type that returns results with a case-insensitive end sequence.
delete()
save()
iendswith
count()
47. A convenience method for constructing an object and saving it all in one step.
Q(question__istartswith='What')
contains
create(**kwargs)
choices tuple
48. 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
many-to-one relationship
order_by(*fields)
week_day
49. Lookup type for date/datetime fields that finds an exact day match.
default
day
intermediate models
iregex
50. 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
default
none()
primary_key
select_related()