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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 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
Meta class
select_related()
class attributes
Proxy model
2. Lookup type that returns results with a case-insensitive end sequence.
iendswith
only(*fields)
iexact
in
3. This represents a collection of objects from your database. It can have zero - one or many filters.
clear() method
Field lookups
regex
QuerySet
4. 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
values(*fields)
in
primary_key
5. 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()
~
exclude(**kwargs)
Proxy model
6. 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.
pickling
update(**kwargs)
ManyToManyField
default
7. The database that will be used if this query is executed now
aggregate(args - *kwargs)
|
db
filter(**kwargs)
8. Manager method used to retrieve every object in a model.
Entry.objects.filter(pub_date__year=2005).delete()
|
all()
Entry.objects.filter(id__gt=4)
9. 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.
get(**kwargs)
update(**kwargs)
using(alias)
id field
10. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
latest(field_name=None)
isnull
month
values_list(*fields)
11. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
year
range
filter chaining
endswith
12. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
exclude(**kwargs)
isnull
ForeignKey
week_day
13. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
week_day
none()
Many-to-many relationship to self
==
14. 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.
Many-to-many relationship through an intermediate model
istartswith
OneToOneField
unique
15. Lookup type that finds a case-insensitive regular expression match.
iregex
year
null
unique
16. This query finds all entries between a start date of start_date and an end date of end_date.
related_name
using(alias)
through argument
Entry.objects.filter(pub_date__range=(start_date - end_date))
17. 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.
filter
Multi-table inheritance
year
week_day
18. 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
contains
pickling
only(*fields)
Many-to-many relationship through an intermediate model
19. Lookup type for date/datetime fields that finds an exact day match.
day
many-to-many relationship
clear() method
Restrictions on field names
20. 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.
none()
Custom model methods
iexact
help_text
21. Lookup type that returns results that fall into an inclusive date range.
istartswith
class type
range
update()
22. Conjuntion operator for Q objects.
exact
&
get(**kwargs)
iregex
23. This gives your model metadata.
Meta class
~
delete()
|
24. This is a criterion that narrow down a QuerySet based on given parameters.
db
filter
count()
pk
25. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.
create(**kwargs)
ordered
contains
null
26. 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.
delete()
iendswith
exists()
get(**kwargs)
27. This query finds all entries with an id greater than 4.
Entry.objects.filter(id__gt=4)
month
latest(field_name=None)
day
28. 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.
ForeignKey
create(**kwargs)
Proxy model
year
29. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
DoesNotExist
distinct()
Custom model methods
Q()
30. 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.
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
when you add new apps to INSTALLED_APPS
Meta class
get(**kwargs)
31. Returns the most recent object in the table - by date - using the field_name provided as the date field.
filter(**kwargs)
Many-to-many relationship to self
get_absolute_url()
latest(field_name=None)
32. 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.
help_text
aggregate(args - *kwargs)
count()
Abstract base class
33. 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)
iterator()
values(*fields)
Model metadata
get_or_create(**kwargs)
34. Lookup type that yields a case-insensitive match.
evaluation
iexact
DoesNotExist
|
35. This query finds all entries with an id in the list [1 - 3 - 4]
Entry.objects.filter(id__in=[1 - 3 - 4])
lte
select_related()
clear() method
36. If you are using this attribute on a ForeignKey or ManyToManyField - you must always specify a unique reverse name for the field.
iexact
Many-to-many relationship through an intermediate model
related_name
evaluation
37. 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
38. 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
|
regex
pk
39. The default for this is the name of the child class followed by '_set'.
iexact
reverse name
iendswith
pk
40. This query updates all the headlines with pub_date in 2007 to read 'Everything is the same'.
Warning
: Invalid argument supplied for foreach() in
/var/www/html/basicversity.com/show_quiz.php
on line
183
41. Negation operator for Q objects.
~
filter(**kwargs)
iteration
iterator()
42. A Python "magic method" that returns a unicode "representation" of any object.
in_bulk(id_list)
__unicode__()
Multi-table inheritance
values(*fields)
43. Lookup type that finds a case-sensitive regular expression match.
get_or_create(**kwargs)
gt
in_bulk(id_list)
regex
44. A convenience method for looking up an object with the given kwargs - creating one if necessary.
clear() method
ManyToManyField
lte
get_or_create(**kwargs)
45. 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
annotate(args - *kwargs)
Proxy model
choices
range
46. Lookup type that returns results greater than a given value.
Q()
gt
reverse()
values_list(*fields)
47. 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
48. 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
choices
exists()
reverse()
intermediate models
49. 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
Q()
none()
Manager methods
Entry.objects.filter(pub_date__year=2005).delete()
50. 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
select_related()
Abstract base class
save()