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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. Defines a many-to-many relationship. You use it just like any other Field type: by including it as a class attribute of your model.
Entry.objects.filter(id__in=[1 - 3 - 4])
range
only(*fields)
ManyToManyField
2. 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
3. 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
Manager
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
all()
day
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.
Restrictions on field names
in
Field lookups
values_list(*fields)
5. 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.
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
default
isnull
endswith
6. This query finds all entries between a start date of start_date and an end date of end_date.
Proxy model
Entry.objects.filter(pub_date__range=(start_date - end_date))
Multi-table inheritance
Abstract base class
7. If this option is True - Django will store empty values as NULL in the database. Default is False.
null
in_bulk(id_list)
day
create(**kwargs)
8. 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.
model
exact
class attributes
F()
9. 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.
iteration
defer(*fields)
get(**kwargs)
ManyToManyField
10. Lookup type that finds a case-insensitive regular expression match.
filter
Many-to-many relationship through an intermediate model
iregex
count()
11. Returns the most recent object in the table - by date - using the field_name provided as the date field.
exists()
isnull
Custom model methods
latest(field_name=None)
12. A convenience method for looking up an object with the given kwargs - creating one if necessary.
get_or_create(**kwargs)
model
==
Manager
13. These methods are intended to do "table-wide" things.
Custom model methods
primary_key
Manager methods
ForeignKey
14. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.
ordered
Q(question__istartswith='What')
isnull
pk
15. Lookup type that returns results less than a given value.
Restrictions on field names
Manager methods
Multi-table inheritance
lt
16. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
many-to-many relationship
relationship spanning
clear() method
latest(field_name=None)
17. 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
filter(**kwargs)
one-to-one relationship
class type
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
18. Conjuntion operator for Q objects.
choices tuple
order_by(*fields)
iexact
&
19. 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
defer(*fields)
class type
Custom model methods
iterator()
20. Lookup type that returns results with a case-sensitive end sequence.
endswith
db
iendswith
one-to-one relationship
21. A convenience method for constructing an object and saving it all in one step.
get(**kwargs)
search
class attributes
create(**kwargs)
22. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
count()
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
month
exists()
23. Lookup type for date/datetime fields that finds a 'day of the week' match.
regex
model
Custom model methods
week_day
24. 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.
OneToOneField
slicing
ForeignKey
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
25. 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
clear() method
choices tuple
Proxy model
Entry.objects.filter(id__in=[1 - 3 - 4])
26. 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)
Many-to-many relationship to self
lte
|
Model metadata
27. 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()
all()
default
when you add new apps to INSTALLED_APPS
28. 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
Entry.objects.filter(id__in=[1 - 3 - 4])
only(*fields)
update(**kwargs)
29. 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.
many-to-one relationship
choices tuple
filter(**kwargs)
many-to-many relationship
30. Returns a new QuerySet containing objects that match the given lookup parameters.
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
help_text
filter(**kwargs)
31. This model method saves a model instance to the database. This method has no return value.
regex
save()
lt
annotate(args - *kwargs)
32. 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.
db
get_absolute_url()
search
none()
33. Lookup type that tests for inclusion in a case-sensitive fashion.
in_bulk(id_list)
startswith
contains
values(*fields)
34. This query finds all entries with an id in the list [1 - 3 - 4]
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
Entry.objects.filter(id__in=[1 - 3 - 4])
using(alias)
exclude(**kwargs)
35. 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
36. 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.
isnull
class type
in_bulk(id_list)
many-to-one relationship
37. a QuerySet can be sliced - using Python's array-slicing syntax.
reverse()
update()
week_day
slicing
38. 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.
==
&
F()
using(alias)
39. Lookup type that returns results with a case-insensitive start sequence.
unique
reverse()
istartswith
DoesNotExist
40. Lookup type that returns results with a case-insensitive end sequence.
istartswith
exact
exclude(**kwargs)
iendswith
41. 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.
iexact
using(alias)
filter(**kwargs)
order_by(*fields)
42. This field is added automatically - but this behavior can be overridden
id field
ForeignKey
annotate(args - *kwargs)
filter(**kwargs)
43. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
many-to-many relationship
in
year
get_or_create(**kwargs)
44. (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.
annotate(args - *kwargs)
iregex
istartswith
Restrictions on field names
45. Lookup type that returns results with a case-sensitive start sequence.
many-to-one relationship
range
startswith
lt
46. 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.
month
choices tuple
gt
Proxy model
47. Exception raised by get(**kwargs) if no items match the query.
DoesNotExist
range
~
Q(question__istartswith='What')
48. 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
Abstract base class
none()
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
endswith
49. 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.
OneToOneField
endswith
exists()
latest(field_name=None)
50. 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.
add()
year
aggregate(args - *kwargs)
Many-to-many relationship to self