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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 gives your model metadata.
exact
Entry.objects.filter(id__in=[1 - 3 - 4])
dates(field - kind - order='ASC')
Meta class

2. Used to get a QuerySet for a model. This is called 'objects' by default.
only(*fields)
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
month
Manager

3. 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.
update()
regex
gte
ordered

4. 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

5. These methods are intended to do "table-wide" things.
Manager methods
select_related()
all()
help_text

6. Fields are specified by these
class attributes
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
ManyToManyField
iexact

7. Performs an SQL update query for the specified fields - and returns the number of rows affected. This method is applied instantly and the only restriction on the QuerySet that is updated is that it can only update columns in the model's main table. F
Entry.objects.filter(pub_date__range=(start_date - end_date))
contains
Manager
update(**kwargs)

8. 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
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
intermediate models
relationship spanning
Q()

9. 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.
Entry.objects.filter(pub_date__year=2005).delete()
Multi-table inheritance
slicing
order_by(*fields)

10. 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()
contains
class type
get(**kwargs)

11. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.
year
Restrictions on field names
class attributes
Proxy model

12. The database that will be used if this query is executed now
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
db
unique
Entry.objects.filter(id__in=[1 - 3 - 4])

13. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
reverse name
distinct()
isnull
choices

14. Lookup type that tests for inclusion in a case-sensitive fashion.
istartswith
many-to-many relationship
filter(**kwargs)
contains

15. 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
Multi-table inheritance
contains
filter(**kwargs)
class type

16. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
exact
isnull
primary_key
istartswith

17. This query finds all entries with an id greater than 4.
unique
filter(**kwargs)
filter chaining
Entry.objects.filter(id__gt=4)

18. 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
==
many-to-one relationship
through argument
F()

19. 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.
year
exact
gt
intermediate models

20. 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.
using(alias)
iexact
Custom model methods
slicing

21. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.
exists()
add()
exclude(**kwargs)
when you add new apps to INSTALLED_APPS

22. Returns the most recent object in the table - by date - using the field_name provided as the date field.
Many-to-many relationship to self
values(*fields)
latest(field_name=None)
Entry.objects.filter(id__gt=4)

23. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.
ManyToManyField
distinct()
many-to-many relationship
ForeignKey

24. If True - the table does not permit duplicate values for this field.
unique
iterator()
save()
in

25. Lookup type that returns results less than a given value.
in_bulk(id_list)
Many-to-many relationship to self
lt
month

26. A Python "magic method" that returns a unicode "representation" of any object.
none()
__unicode__()
Field lookups
in

27. 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.
defer(*fields)
range
slicing
help_text

28. If this option is True - the field is allowed to be blank. Default is False.
blank
&
select_related()
pickling

29. 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)
isnull
clear() method
==
Model metadata

30. 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
istartswith
iteration
Model metadata

31. 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
related_name
exists()
Entry.objects.filter(id__gt=4)
many-to-many relationship

32. Returns the object matching the given lookup parameters
search
get(**kwargs)
model
save()

33. 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
all()
ordered
~

34. 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
select_related()
unique
none()
&

35. 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()
exists()
get(**kwargs)
evaluation

36. Lookup type that yields a case-insensitive match.
null
unique
gt
iexact

37. Keyword shortcut for looking up an object by primary key.
get_absolute_url()
ordered
pk
Entry.objects.filter(id__gt=4)

38. These add custom "row-level" functionality to your objects. These act on a particular model instance.
model
unique
Custom model methods
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.

39. When to run syncdb
values(*fields)
when you add new apps to INSTALLED_APPS
unique
day

40. The default for this is the name of the child class followed by '_set'.
reverse name
values_list(*fields)
order_by(*fields)
add()

41. Exception raised by get(**kwargs) if more than one item matches the query.
pickling
MultipleObjectsReturned
Many-to-many relationship to self
evaluation

42. 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

43. If True - this field is the primary key for the model.
primary_key
model
iendswith
month

44. Lookup type that returns results greater than a given value.
startswith
Abstract base class
gt
Many-to-many relationship to self

45. Exception raised by get(**kwargs) if no items match the query.
get(**kwargs)
ordered
iteration
DoesNotExist

46. 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.
Many-to-many relationship through an intermediate model
get_or_create(**kwargs)
help_text
filter(**kwargs)

47. Lookup type for date/datetime fields that finds a 'day of the week' match.
none()
DoesNotExist
week_day
filter

48. 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
get_or_create(**kwargs)
MultipleObjectsReturned
iterator()
Entry.objects.filter(id__gt=4)

49. 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()
month
filter
get_absolute_url()

50. A convenience method for looking up an object with the given kwargs - creating one if necessary.
get_or_create(**kwargs)
values_list(*fields)
year
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)