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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. (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.
month
gt
model
Restrictions on field names
2. 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()
aggregate(args - *kwargs)
range
week_day
3. A convenience method for constructing an object and saving it all in one step.
gte
~
id field
create(**kwargs)
4. Lookup type that returns results with a case-sensitive end sequence.
gt
many-to-many relationship
get_absolute_url()
endswith
5. This is a criterion that narrow down a QuerySet based on given parameters.
istartswith
ManyToManyField
through argument
filter
6. 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.
related_name
~
pickling
endswith
7. These are specified as keyword arguments to the QuerySet methods filter() - exclude() and get(). These take the form field__lookuptype=value .
using(alias)
null
search
Field lookups
8. This query finds all entries between a start date of start_date and an end date of end_date.
Entry.objects.filter(pub_date__range=(start_date - end_date))
filter
count()
model
9. Lookup type that returns results that fall into an inclusive date range.
model
Custom model methods
|
range
10. Lookup type for date/datetime fields that finds a 'day of the week' match.
related_name
in
help_text
week_day
11. This represents a collection of objects from your database. It can have zero - one or many filters.
create(**kwargs)
lte
one-to-one relationship
QuerySet
12. 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
choices
delete()
isnull
annotate(args - *kwargs)
13. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
help_text
ManyToManyField
in
year
14. 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.
Entry.objects.filter(pub_date__year=2005).delete()
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
week_day
filter chaining
15. Lookup type that returns results with a case-insensitive end sequence.
through argument
iendswith
choices tuple
blank
16. This model method is used for updating a ManyToManyField.
add()
defer(*fields)
ManyToManyField
Custom model methods
17. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
iendswith
defer(*fields)
many-to-many relationship
aggregate(args - *kwargs)
18. 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.
filter
Many-to-many relationship to self
add()
Field lookups
19. Each one of these is a Python class that subclasses django.db.models.Model. Each attribute of one of these represents a database field.
iterator()
primary_key
model
==
20. Negation operator for Q objects.
Many-to-many relationship through an intermediate model
relationship spanning
values_list(*fields)
~
21. This query finds all entries with an id in the list [1 - 3 - 4]
regex
class type
ordered
Entry.objects.filter(id__in=[1 - 3 - 4])
22. Lookup type that tests for inclusion in a case-sensitive fashion.
contains
~
Abstract base class
pk
23. This field is added automatically - but this behavior can be overridden
gt
week_day
id field
defer(*fields)
24. Returns the most recent object in the table - by date - using the field_name provided as the date field.
latest(field_name=None)
ordered
lt
&
25. 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
none()
get_or_create(**kwargs)
search
gte
26. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.
Entry.objects.filter(id__in=[1 - 3 - 4])
Manager
exclude(**kwargs)
choices
27. 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
select_related()
Entry.objects.filter(pub_date__year=2005).delete()
Many-to-many relationship to self
Abstract base class
28. The database that will be used if this query is executed now
db
Restrictions on field names
day
values_list(*fields)
29. 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
iteration
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
through argument
choices tuple
30. Returns the object matching the given lookup parameters
get(**kwargs)
get_absolute_url()
iendswith
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
31. 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
add()
startswith
day
32. 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.
==
aggregate(args - *kwargs)
get_absolute_url()
Field lookups
33. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
count()
Entry.objects.filter(pub_date__range=(start_date - end_date))
isnull
iteration
34. 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.
iterator()
order_by(*fields)
id field
isnull
35. This method immediately deletes the object and has no return value.
==
delete()
reverse name
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
36. A Python "magic method" that returns a unicode "representation" of any object.
only(*fields)
year
aggregate(args - *kwargs)
__unicode__()
37. 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.
exclude(**kwargs)
gte
add()
choices tuple
38. Lookup type that returns results in a given list.
in
db
many-to-many relationship
through argument
39. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
get(**kwargs)
get_or_create(**kwargs)
distinct()
filter chaining
40. 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.
only(*fields)
blank
update()
primary_key
41. 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
in
exact
OneToOneField
42. These methods are intended to do "table-wide" things.
Manager methods
iterator()
ForeignKey
==
43. Lookup type that yields an "exact" match. If you don't provide a lookup type -- that is - if your keyword argument doesn't contain a double underscore -- the lookup type is assumed to be of this sort.
exact
istartswith
Many-to-many relationship to self
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
44. 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
many-to-one relationship
pk
Entry.objects.filter(pub_date__year=2005).delete()
45. 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.
using(alias)
values_list(*fields)
ManyToManyField
Entry.objects.filter(pub_date__range=(start_date - end_date))
46. 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
47. 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()
exclude(**kwargs)
latest(field_name=None)
evaluation
Entry.objects.filter(id__in=[1 - 3 - 4])
48. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
none()
model
Field lookups
month
49. A Q object that asks for entries with a question value that start with 'Who' or do not have a publication date of 2005.
Warning
: Invalid argument supplied for foreach() in
/var/www/html/basicversity.com/show_quiz.php
on line
183
50. Lookup type that returns results less than or equal to a given value.
lte
QuerySet
get(**kwargs)
delete()