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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. 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.
pickling
~
defer(*fields)
Many-to-many relationship to self
2. Disjunction operator for Q objects.
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
regex
|
relationship spanning
3. 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
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
dates(field - kind - order='ASC')
count()
Abstract base class
4. This query finds all entries with an id in the list [1 - 3 - 4]
Meta class
delete()
Entry.objects.filter(id__in=[1 - 3 - 4])
default
5. 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
delete()
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
class type
6. 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
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
month
Custom model methods
7. 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
help_text
count()
all()
update()
8. If True - the table does not permit duplicate values for this field.
search
QuerySet
aggregate(args - *kwargs)
unique
9. If this option is True - Django will store empty values as NULL in the database. Default is False.
null
aggregate(args - *kwargs)
one-to-one relationship
default
10. 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
11. 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
latest(field_name=None)
filter chaining
only(*fields)
year
12. 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()
when you add new apps to INSTALLED_APPS
many-to-one relationship
evaluation
Abstract base class
13. Lookup type that returns results with a case-insensitive end sequence.
contains
iendswith
Many-to-many relationship to self
delete()
14. These are specified as keyword arguments to the QuerySet methods filter() - exclude() and get(). These take the form field__lookuptype=value .
annotate(args - *kwargs)
Field lookups
save()
filter(**kwargs)
15. a QuerySet can be sliced - using Python's array-slicing syntax.
when you add new apps to INSTALLED_APPS
slicing
isnull
unique
16. 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()
clear() method
Custom model methods
iendswith
17. 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
values_list(*fields)
class type
through argument
Q()
18. To activate your models
month
latest(field_name=None)
range
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
19. Exception raised by get(**kwargs) if more than one item matches the query.
filter(**kwargs)
Q(question__istartswith='What')
MultipleObjectsReturned
Entry.objects.filter(pub_date__range=(start_date - end_date))
20. 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
help_text
values(*fields)
Q()
21. Lookup type that returns results with a case-insensitive start sequence.
isnull
MultipleObjectsReturned
istartswith
filter chaining
22. Lookup type for date/datetime fields that finds an exact day match.
day
lte
range
many-to-one relationship
23. Lookup type that finds a case-insensitive regular expression match.
class attributes
iregex
evaluation
delete()
24. Lookup type that returns results less than or equal to a given value.
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
lte
iregex
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
25. 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)
Entry.objects.filter(pub_date__year=2005).delete()
ordered
Multi-table inheritance
Model metadata
26. Can be used to remove all many-to-many relationships for an instance
reverse()
iterator()
class attributes
clear() method
27. 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.
count()
filter(**kwargs)
~
Multi-table inheritance
28. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
month
lt
order_by(*fields)
select_related()
29. 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.
ManyToManyField
lte
iexact
get(**kwargs)
30. Here - you can't use add - create - or assignment (i.e. - beatles.members = [...]) to create relationships. You need to specify all the detail for the relationship required by the intermediate model.
select_related()
Many-to-many relationship through an intermediate model
values(*fields)
Multi-table inheritance
31. 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)
exclude(**kwargs)
Abstract base class
distinct()
32. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
get(**kwargs)
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
filter chaining
distinct()
33. Lookup type that returns results greater than or equal to a given value.
unique
OneToOneField
isnull
gte
34. Lookup type that returns results that fall into an inclusive date range.
ManyToManyField
db
null
range
35. The default for this is the name of the child class followed by '_set'.
ManyToManyField
__unicode__()
iteration
reverse name
36. 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
class type
Manager
reverse()
F()
37. Fields are specified by these
Entry.objects.filter(id__in=[1 - 3 - 4])
only(*fields)
class attributes
Manager methods
38. 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.
iexact
DoesNotExist
in_bulk(id_list)
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
39. Lookup type for date/datetime fields that finds a 'day of the week' match.
week_day
help_text
count()
Model metadata
40. This field is added automatically - but this behavior can be overridden
ordered
intermediate models
db
id field
41. Lookup type that returns results with a case-sensitive start sequence.
defer(*fields)
startswith
Field lookups
__unicode__()
42. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
id field
count()
save()
reverse()
43. Lookup type that tests for inclusion in a case-sensitive fashion.
primary_key
reverse()
OneToOneField
contains
44. 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.
istartswith
update()
|
DoesNotExist
45. 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
lt
range
Model metadata
46. 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
47. 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
order_by(*fields)
exclude(**kwargs)
unique
48. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.
exclude(**kwargs)
all()
gt
dates(field - kind - order='ASC')
49. Conjuntion operator for Q objects.
ordered
&
reverse name
gte
50. 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
Model metadata
exists()
Proxy model
id field