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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. When to run syncdb
when you add new apps to INSTALLED_APPS
search
filter(**kwargs)
startswith
2. This gives your model metadata.
Meta class
dates(field - kind - order='ASC')
all()
one-to-one relationship
3. Evaluates the QuerySet (by performing the query) and returns an iterator over the results. A QuerySet typically caches its results internally so that repeated evaluations do not result in additional queries; this method will instead read results dire
iterator()
ForeignKey
day
in
4. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
count()
gt
Many-to-many relationship through an intermediate model
week_day
5. If this option is True - the field is allowed to be blank. Default is False.
blank
lte
clear() method
class type
6. 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.
OneToOneField
evaluation
Q()
ManyToManyField
7. This is a criterion that narrow down a QuerySet based on given parameters.
filter
iterator()
model
OneToOneField
8. 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()
aggregate(args - *kwargs)
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
Custom model methods
9. 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.
only(*fields)
filter(**kwargs)
OneToOneField
Entry.objects.filter(pub_date__range=(start_date - end_date))
10. 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.
iterator()
intermediate models
reverse name
help_text
11. 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
Entry.objects.filter(pub_date__range=(start_date - end_date))
select_related()
values(*fields)
in_bulk(id_list)
12. Lookup type that returns results with a case-sensitive end sequence.
endswith
values_list(*fields)
in_bulk(id_list)
iendswith
13. 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
ordered
Abstract base class
primary_key
create(**kwargs)
14. Manager method used to retrieve every object in a model.
all()
QuerySet
get(**kwargs)
count()
15. Returns True if the QuerySet contains any results - and False if not. This tries to perform the query in the simplest and fastest way possible - but it does execute nearly the same query. This means that calling this method on a queryset is faster th
iterator()
~
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
exists()
16. Lookup type that returns results less than or equal to a given value.
model
lte
count()
Q(question__istartswith='What')
17. 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.
delete()
Q(question__istartswith='What')
filter
18. 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
endswith
month
F()
week_day
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.
add()
filter(**kwargs)
model
all()
20. 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
21. Negation operator for Q objects.
~
clear() method
iendswith
annotate(args - *kwargs)
22. Can be used to remove all many-to-many relationships for an instance
Entry.objects.filter(id__in=[1 - 3 - 4])
isnull
Manager methods
clear() method
23. Lookup type that returns results that fall into an inclusive date range.
count()
Entry.objects.filter(pub_date__year=2005).delete()
range
choices tuple
24. 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.
class attributes
using(alias)
one-to-one relationship
annotate(args - *kwargs)
25. Lookup type that returns results with a case-insensitive end sequence.
add()
iendswith
Many-to-many relationship through an intermediate model
year
26. 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.
pickling
==
in_bulk(id_list)
annotate(args - *kwargs)
27. These are specified as keyword arguments to the QuerySet methods filter() - exclude() and get(). These take the form field__lookuptype=value .
Field lookups
year
in_bulk(id_list)
order_by(*fields)
28. 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.
id field
delete()
latest(field_name=None)
model
29. 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
count()
|
defer(*fields)
ForeignKey
30. 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.
one-to-one relationship
many-to-one relationship
values_list(*fields)
filter chaining
31. 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
__unicode__()
F()
model
32. 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
count()
all()
search
Manager methods
33. This query deletes all Entry objects with a pub_date year of 2005.
Entry.objects.filter(pub_date__year=2005).delete()
when you add new apps to INSTALLED_APPS
lte
delete()
34. This model method saves a model instance to the database. This method has no return value.
save()
day
all()
in_bulk(id_list)
35. Returns a new QuerySet containing objects that match the given lookup parameters.
Restrictions on field names
filter(**kwargs)
distinct()
all()
36. This model method is used for updating a ManyToManyField.
Entry.objects.filter(id__in=[1 - 3 - 4])
Manager
help_text
add()
37. This method immediately deletes the object and has no return value.
update(**kwargs)
save()
delete()
iendswith
38. This query finds all entries with an id greater than 4.
count()
Entry.objects.filter(id__gt=4)
lte
evaluation
39. 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.
F()
Multi-table inheritance
get(**kwargs)
filter chaining
40. Lookup type that tests for inclusion in a case-sensitive fashion.
MultipleObjectsReturned
regex
only(*fields)
contains
41. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
Restrictions on field names
in_bulk(id_list)
Manager
many-to-many relationship
42. 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
43. 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.
gt
pickling
relationship spanning
istartswith
44. 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
Proxy model
order_by(*fields)
aggregate(args - *kwargs)
annotate(args - *kwargs)
45. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.
add()
QuerySet
exclude(**kwargs)
Custom model methods
46. 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
clear() method
select_related()
choices
47. Keyword shortcut for looking up an object by primary key.
pk
Q(question__istartswith='What')
class attributes
select_related()
48. Lookup type that yields a case-insensitive match.
get(**kwargs)
iexact
month
iterator()
49. Defined by a OneToOneField. You use it just like any other Field type: by including it as a class attribute of your model.
iteration
through argument
one-to-one relationship
intermediate models
50. If you are using this attribute on a ForeignKey or ManyToManyField - you must always specify a unique reverse name for the field.
pk
day
related_name
F()