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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.
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. Used to get a QuerySet for a model. This is called 'objects' by default.
Manager
values(*fields)
in
using(alias)

2. Lookup type that returns results greater than or equal to a given value.
choices tuple
gte
values_list(*fields)
&

3. If this option is True - the field is allowed to be blank. Default is False.
reverse()
none()
blank
db

4. Lookup type that returns results that fall into an inclusive date range.
default
==
range
Custom model methods

5. 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)
pickling
Custom model methods
gt

6. Lookup type that returns results less than a given value.
delete()
dates(field - kind - order='ASC')
lt
unique

7. 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.
unique
get(**kwargs)
get_absolute_url()
all()

8. Keyword shortcut for looking up an object by primary key.
pk
Abstract base class
__unicode__()
exists()

9. 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
month
choices
iterator()
update()

10. 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
count()
Custom model methods
F()
in_bulk(id_list)

11. Lookup type for date/datetime fields that finds a 'day of the week' match.
distinct()
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
week_day
exact

12. 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.
only(*fields)
default
help_text
defer(*fields)

13. This is a criterion that narrow down a QuerySet based on given parameters.
filter
slicing
Q()
lt

14. 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.
null
Field lookups
Q()
Abstract base class

15. When to run syncdb
pickling
get(**kwargs)
filter(**kwargs)
when you add new apps to INSTALLED_APPS

16. Returns the most recent object in the table - by date - using the field_name provided as the date field.
latest(field_name=None)
iterator()
primary_key
Q(question__startswith='Who') | ~Q(pub_date__year=2005)

17. A QuerySet is iterable - and it executes its database query the first time you iterate over it.
evaluation
reverse name
clear() method
iteration

18. The default for this is the name of the child class followed by '_set'.
reverse name
order_by(*fields)
week_day
F()

19. 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.
lt
regex
Many-to-many relationship to self
get(**kwargs)

20. This represents a collection of objects from your database. It can have zero - one or many filters.
range
QuerySet
blank
month

21. 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
values_list(*fields)
~
Q(question__istartswith='What')

22. 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.
ForeignKey
many-to-many relationship
lt
iterator()

23. This model method saves a model instance to the database. This method has no return value.
ManyToManyField
save()
year
istartswith

24. Returns a new QuerySet containing objects that match the given lookup parameters.
clear() method
endswith
filter(**kwargs)
using(alias)

25. If True - the table does not permit duplicate values for this field.
|
F()
endswith
unique

26. This field is added automatically - but this behavior can be overridden
startswith
values_list(*fields)
in
id field

27. 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.
intermediate models
reverse()
all()
MultipleObjectsReturned

28. 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.
values_list(*fields)
many-to-many relationship
many-to-one relationship
in

29. Lookup type that returns results less than or equal to a given value.
lte
update()
month
iexact

30. Lookup type that finds a case-insensitive regular expression match.
iregex
isnull
filter chaining
values_list(*fields)

31. Lookup type that returns results in a given list.
in
values(*fields)
dates(field - kind - order='ASC')
defer(*fields)

32. 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
save()
in
filter(**kwargs)

33. 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)
exact
contains
Model metadata
Manager

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
search
when you add new apps to INSTALLED_APPS
get_or_create(**kwargs)
none()

35. This query uses an F object to increment the pingback count for every entry in the blog.

36. Conjuntion operator for Q objects.
startswith
choices
Entry.objects.filter(pub_date__year=2005).delete()
&

37. 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
regex
all()
db
help_text

38. 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.
count()
Entry.objects.filter(id__in=[1 - 3 - 4])
only(*fields)
filter chaining

39. 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.
delete()
order_by(*fields)
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
none()

40. This query finds all entries between a start date of start_date and an end date of end_date.
year
db
choices tuple
Entry.objects.filter(pub_date__range=(start_date - end_date))

41. 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.
in_bulk(id_list)
choices tuple
__unicode__()
Entry.objects.filter(id__gt=4)

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

43. 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.
month
Proxy model
using(alias)
search

44. Lookup type that tests for inclusion in a case-sensitive fashion.
contains
when you add new apps to INSTALLED_APPS
in
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')

45. 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
pickling
class type
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
exact

46. Negation operator for Q objects.
select_related()
~
lte
endswith

47. 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
regex
Manager
Proxy model
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')

48. 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.
day
Q(question__startswith='Who') | ~Q(pub_date__year=2005)
distinct()
aggregate(args - *kwargs)

49. (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.
filter chaining
get(**kwargs)
Restrictions on field names
help_text

50. a QuerySet can be sliced - using Python's array-slicing syntax.
dates(field - kind - order='ASC')
Proxy model
slicing
filter