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Django Queryset

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. Lookup type that returns results with a case-insensitive start sequence.
istartswith
iexact
Q()
distinct()

2. To activate your models
search
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
latest(field_name=None)
distinct()

3. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
unique
Q()
defer(*fields)
month

4. These add custom "row-level" functionality to your objects. These act on a particular model instance.
Custom model methods
contains
model
lt

5. Lookup type that returns results less than a given value.
lt
through argument
Manager
filter(**kwargs)

6. 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
annotate(args - *kwargs)
day
all()
Entry.objects.filter(pub_date__year=2005).delete()

7. A convenience method for constructing an object and saving it all in one step.
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
related_name
class type
create(**kwargs)

8. 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.
help_text
month
clear() method
range

9. This query finds all entries between a start date of start_date and an end date of end_date.
exists()
relationship spanning
Entry.objects.filter(pub_date__range=(start_date - end_date))
db

10. Negation operator for Q objects.
update(**kwargs)
distinct()
~
through argument

11. 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
class type
iregex
iteration
id field

12. Exception raised by get(**kwargs) if more than one item matches the query.
help_text
MultipleObjectsReturned
iendswith
many-to-one relationship

13. A Q object that encapsulates queries for entries with a question value that starts with 'What' in a case-insensitive fashion.

14. 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
get_or_create(**kwargs)
Entry.objects.filter(pub_date__year=2005).delete()
Model metadata
exists()

15. Lookup type that returns results with a case-insensitive end sequence.
Proxy model
iendswith
week_day
clear() method

16. 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)
month
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
pk
Model metadata

17. 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
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
Manager
iendswith

18. Lookup type that finds a case-insensitive regular expression match.
relationship spanning
endswith
iregex
update(**kwargs)

19. Returns a new QuerySet containing objects that match the given lookup parameters.
in
only(*fields)
primary_key
filter(**kwargs)

20. 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
values(*fields)
annotate(args - *kwargs)
Q()
none()

21. 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.
iendswith
through argument
reverse()
week_day

22. 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.
get(**kwargs)
intermediate models
|
choices tuple

23. Lookup type that returns results greater than a given value.
day
isnull
gt
ForeignKey

24. Manager method used to retrieve every object in a model.
all()
relationship spanning
reverse name
Model metadata

25. Conjuntion operator for Q objects.
distinct()
&
ForeignKey
OneToOneField

26. Returns the most recent object in the table - by date - using the field_name provided as the date field.
gte
iteration
latest(field_name=None)
Entry.objects.filter(pub_date__range=(start_date - end_date))

27. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.
count()
choices tuple
in_bulk(id_list)
many-to-one relationship

28. If this option is True - Django will store empty values as NULL in the database. Default is False.
none()
get_or_create(**kwargs)
class type
null

29. This query updates all the headlines with pub_date in 2007 to read 'Everything is the same'.

30. 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
unique
through argument
contains
order_by(*fields)

31. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.
values(*fields)
get(**kwargs)
day
filter(**kwargs)

32. 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
exists()
Entry.objects.filter(pub_date__range=(start_date - end_date))
many-to-one relationship
relationship spanning

33. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.
ordered
slicing
choices
iexact

34. A Q object that asks for entries with a question value that start with 'Who' or do not have a publication date of 2005.

35. 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.
update(**kwargs)
filter(**kwargs)
Restrictions on field names
delete()

36. 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.
values(*fields)
Entry.objects.filter(pub_date__year=2005).delete()
default
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')

37. 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
many-to-many relationship
through argument
Entry.objects.filter(id__in=[1 - 3 - 4])

38. 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.
unique
Many-to-many relationship to self
Custom model methods
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)

39. This method immediately deletes the object and has no return value.
OneToOneField
delete()
values_list(*fields)
day

40. These are specified as keyword arguments to the QuerySet methods filter() - exclude() and get(). These take the form field__lookuptype=value .
get_or_create(**kwargs)
Field lookups
filter(**kwargs)
iendswith

41. A Python "magic method" that returns a unicode "representation" of any object.
db
many-to-many relationship
Proxy model
__unicode__()

42. This model method saves a model instance to the database. This method has no return value.
help_text
save()
count()
Entry.objects.filter(pub_date__year=2005).delete()

43. 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.
db
filter(**kwargs)
ForeignKey
related_name

44. 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.
values(*fields)
using(alias)
isnull
create(**kwargs)

45. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.
get(**kwargs)
using(alias)
values(*fields)
distinct()

46. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
ManyToManyField
Model metadata
distinct()
model

47. This represents a collection of objects from your database. It can have zero - one or many filters.
QuerySet
gte
iterator()
choices

48. Lookup type that returns results with a case-sensitive start sequence.
startswith
Q(question__istartswith='What')
many-to-one relationship
create(**kwargs)

49. 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
only(*fields)
latest(field_name=None)
null
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')

50. Fields are specified by these
Many-to-many relationship to self
istartswith
MultipleObjectsReturned
class attributes