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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. This query finds all entries between a start date of start_date and an end date of end_date.
update()
latest(field_name=None)
get(**kwargs)
Entry.objects.filter(pub_date__range=(start_date - end_date))
2. 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.
reverse()
exists()
many-to-one relationship
annotate(args - *kwargs)
3. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
exists()
many-to-many relationship
==
create(**kwargs)
4. 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.
ordered
intermediate models
Abstract base class
choices
5. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
model
month
choices tuple
6. 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
day
distinct()
primary_key
all()
7. This represents a collection of objects from your database. It can have zero - one or many filters.
day
in
QuerySet
Q(question__istartswith='What')
8. 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(id__gt=4)
ordered
get(**kwargs)
count()
9. 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
save()
gt
get_absolute_url()
annotate(args - *kwargs)
10. 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
intermediate models
|
gt
reverse()
11. This tells Django how to calculate the URL for an object. Django uses this in its admin interface - and any time it needs to figure out a URL for an object.
count()
get_absolute_url()
lte
regex
12. 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
contains
regex
select_related()
update()
13. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
Manager
values_list(*fields)
isnull
only(*fields)
14. If this option is True - the field is allowed to be blank. Default is False.
gte
get_or_create(**kwargs)
unique
blank
15. a QuerySet can be sliced - using Python's array-slicing syntax.
startswith
get(**kwargs)
|
slicing
16. 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
get_or_create(**kwargs)
Custom model methods
when you add new apps to INSTALLED_APPS
17. 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.
pk
values_list(*fields)
Model metadata
annotate(args - *kwargs)
18. Lookup type that returns results in a given list.
annotate(args - *kwargs)
many-to-many relationship
in
ForeignKey
19. 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
order_by(*fields)
Many-to-many relationship to self
only(*fields)
20. Lookup type that returns results greater than a given value.
Meta class
gt
week_day
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
21. 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.
Many-to-many relationship to self
reverse name
ForeignKey
pk
22. Used to get a QuerySet for a model. This is called 'objects' by default.
Manager
ManyToManyField
|
contains
23. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
lt
values(*fields)
reverse name
distinct()
24. 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
OneToOneField
reverse()
gte
Abstract base class
25. Lookup type that returns results that fall into an inclusive date range.
intermediate models
range
model
iendswith
26. Lookup type that yields a case-insensitive match.
iexact
none()
relationship spanning
ordered
27. 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
relationship spanning
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
delete()
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
28. Lookup type that returns results with a case-sensitive start sequence.
startswith
choices tuple
lte
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
29. This method immediately deletes the object and has no return value.
choices
isnull
Manager
delete()
30. Returns a new QuerySet containing objects that match the given lookup parameters.
lte
filter(**kwargs)
update()
reverse()
31. Returns the most recent object in the table - by date - using the field_name provided as the date field.
iexact
Entry.objects.filter(pub_date__range=(start_date - end_date))
latest(field_name=None)
isnull
32. Each one of these is a Python class that subclasses django.db.models.Model. Each attribute of one of these represents a database field.
reverse name
Entry.objects.filter(id__gt=4)
choices
model
33. 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
&
get_absolute_url()
all()
34. This query finds all entries with an id greater than 4.
aggregate(args - *kwargs)
order_by(*fields)
Field lookups
Entry.objects.filter(id__gt=4)
35. This query deletes all Entry objects with a pub_date year of 2005.
Meta class
relationship spanning
ManyToManyField
Entry.objects.filter(pub_date__year=2005).delete()
36. 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.
update(**kwargs)
__unicode__()
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
aggregate(args - *kwargs)
37. These add custom "row-level" functionality to your objects. These act on a particular model instance.
many-to-one relationship
lte
Custom model methods
update(**kwargs)
38. 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.
DoesNotExist
==
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
model
39. Lookup type that returns results less than or equal to a given value.
Model metadata
in
Entry.objects.filter(pub_date__range=(start_date - end_date))
lte
40. 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.
week_day
reverse()
day
iterator()
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
Q(question__istartswith='What')
year
class type
class attributes
42. Lookup type for date/datetime fields that finds a 'day of the week' match.
week_day
Abstract base class
clear() method
|
43. 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
44. 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.
help_text
in_bulk(id_list)
create(**kwargs)
ordered
45. 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
class type
range
iteration
defer(*fields)
46. Lookup type that returns results with a case-insensitive end sequence.
only(*fields)
exists()
pickling
iendswith
47. Disjunction operator for Q objects.
delete()
Meta class
many-to-many relationship
|
48. 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.
id field
exclude(**kwargs)
search
gte
49. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
pickling
exclude(**kwargs)
all()
year
50. Exception raised by get(**kwargs) if more than one item matches the query.
MultipleObjectsReturned
Manager
endswith
Q()