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Django Queryset

Subject : it-skills

Instructions:

Answer 50 questions in 15 minutes.
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Match each statement with the correct term.
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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. This query finds all entries with an id greater than 4.
Entry.objects.filter(id__gt=4)
reverse()
choices tuple
iregex

2. Returns the most recent object in the table - by date - using the field_name provided as the date field.
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
intermediate models
regex
latest(field_name=None)

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

4. Manager method used to retrieve every object in a model.
all()
Custom model methods
Manager methods
get_absolute_url()

5. 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
gte
clear() method
F()
in_bulk(id_list)

6. Negation operator for Q objects.
~
when you add new apps to INSTALLED_APPS
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
Model metadata

7. 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.
relationship spanning
slicing
Multi-table inheritance
Entry.objects.filter(id__in=[1 - 3 - 4])

8. Lookup type that returns results greater than a given value.
select_related()
QuerySet
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
gt

9. 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

10. This gives your model metadata.
search
gte
pickling
Meta class

11. Lookup type that finds a case-insensitive regular expression match.
filter(**kwargs)
iregex
Many-to-many relationship through an intermediate model
none()

12. 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.
range
OneToOneField
aggregate(args - *kwargs)
null

13. 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
add()
when you add new apps to INSTALLED_APPS
only(*fields)

14. a QuerySet can be sliced - using Python's array-slicing syntax.
ForeignKey
many-to-many relationship
none()
slicing

15. Lookup type that returns results with a case-sensitive start sequence.
startswith
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
==
|

16. 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(pub_date__range=(start_date - end_date))
class attributes

17. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
distinct()
iregex
lte
Custom model methods

18. 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()
one-to-one relationship
default
evaluation
choices

19. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.
Entry.objects.filter(pub_date__range=(start_date - end_date))
Entry.objects.filter(id__gt=4)
Custom model methods
filter(**kwargs)

20. 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()
filter(**kwargs)
delete()
id field

21. 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.
help_text
choices tuple
lte
ordered

22. This is a criterion that narrow down a QuerySet based on given parameters.
istartswith
all()
delete()
filter

23. Returns a new QuerySet containing objects that match the given lookup parameters.
in
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
Many-to-many relationship to self
filter(**kwargs)

24. 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

25. 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
distinct()
iexact
exists()
many-to-one relationship

26. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.
choices
&
values(*fields)
get_absolute_url()

27. 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.
gte
aggregate(args - *kwargs)
count()
class attributes

28. 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
through argument
annotate(args - *kwargs)
delete()
reverse()

29. If this option is True - the field is allowed to be blank. Default is False.
OneToOneField
blank
iregex
Q(question__istartswith='What')

30. 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
select_related()
pk
Q()
class attributes

31. Lookup type that tests for inclusion in a case-sensitive fashion.
only(*fields)
aggregate(args - *kwargs)
contains
add()

32. Keyword shortcut for looking up an object by primary key.
MultipleObjectsReturned
pk
gte
Manager

33. 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.
get(**kwargs)
in
exact
F()

34. 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.
Model metadata
ForeignKey
exists()
update()

35. Returns the object matching the given lookup parameters
get(**kwargs)
many-to-one relationship
filter chaining
regex

36. The database that will be used if this query is executed now
Multi-table inheritance
select_related()
pk
db

37. 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.
Q()
ForeignKey
Entry.objects.filter(id__gt=4)
aggregate(args - *kwargs)

38. Each one of these is a Python class that subclasses django.db.models.Model. Each attribute of one of these represents a database field.
regex
using(alias)
Entry.objects.filter(pub_date__range=(start_date - end_date))
model

39. This query finds all entries between a start date of start_date and an end date of end_date.
day
Entry.objects.filter(pub_date__range=(start_date - end_date))
pickling
help_text

40. 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
using(alias)
create(**kwargs)
annotate(args - *kwargs)

41. Used to get a QuerySet for a model. This is called 'objects' by default.
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
month
defer(*fields)
Manager

42. Lookup type that returns results in a given list.
in
Entry.objects.filter(id__gt=4)
update(**kwargs)
values(*fields)

43. 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.
get_absolute_url()
Manager methods
iendswith
iregex

44. Can be used to remove all many-to-many relationships for an instance
endswith
DoesNotExist
clear() method
when you add new apps to INSTALLED_APPS

45. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
id field
==
intermediate models
create(**kwargs)

46. The default for this is the name of the child class followed by '_set'.
Q()
Model metadata
when you add new apps to INSTALLED_APPS
reverse name

47. 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.
regex
choices
Meta class
Q(question__startswith='Who') | ~Q(pub_date__year=2005)

48. Lookup type that returns results less than a given value.
lt
many-to-one relationship
Manager
class type

49. 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.
create(**kwargs)
Many-to-many relationship through an intermediate model
Multi-table inheritance
unique

50. This query finds all entries with an id in the list [1 - 3 - 4]
Entry.objects.filter(id__in=[1 - 3 - 4])
MultipleObjectsReturned
Q(question__istartswith='What')
isnull