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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. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.
iendswith
|
choices tuple
==
2. 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.
3. 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.
exact
week_day
search
month
4. 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
latest(field_name=None)
intermediate models
evaluation
5. 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.
Q()
MultipleObjectsReturned
day
update()
6. If True - the table does not permit duplicate values for this field.
save()
null
unique
Many-to-many relationship to self
7. 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
db
defer(*fields)
ForeignKey
get_absolute_url()
8. 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.
Entry.objects.filter(pub_date__range=(start_date - end_date))
delete()
order_by(*fields)
when you add new apps to INSTALLED_APPS
9. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.
db
Entry.objects.filter(id__gt=4)
intermediate models
values(*fields)
10. Disjunction operator for Q objects.
F()
one-to-one relationship
|
in_bulk(id_list)
11. 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
delete()
select_related()
exists()
Restrictions on field names
12. Used to get a QuerySet for a model. This is called 'objects' by default.
Manager
all()
lte
relationship spanning
13. A convenience method for constructing an object and saving it all in one step.
primary_key
Meta class
create(**kwargs)
lte
14. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.
exclude(**kwargs)
only(*fields)
slicing
~
15. Returns the most recent object in the table - by date - using the field_name provided as the date field.
choices tuple
latest(field_name=None)
QuerySet
one-to-one relationship
16. This query finds all entries with an id in the list [1 - 3 - 4]
QuerySet
Entry.objects.filter(id__in=[1 - 3 - 4])
many-to-one relationship
Restrictions on field names
17. 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.
__unicode__()
blank
filter(**kwargs)
get_absolute_url()
18. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.
exclude(**kwargs)
add()
ordered
ForeignKey
19. Lookup type that returns results with a case-sensitive end sequence.
iteration
clear() method
endswith
null
20. This represents a collection of objects from your database. It can have zero - one or many filters.
QuerySet
iterator()
select_related()
update(**kwargs)
21. 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
iexact
blank
get(**kwargs)
22. 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
update(**kwargs)
none()
using(alias)
iregex
23. a QuerySet can be sliced - using Python's array-slicing syntax.
Multi-table inheritance
slicing
lte
aggregate(args - *kwargs)
24. Conjuntion operator for Q objects.
&
exact
order_by(*fields)
Field lookups
25. Fields are specified by these
class attributes
null
QuerySet
Field lookups
26. Lookup type that yields a case-insensitive match.
iexact
ForeignKey
update()
Field lookups
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.
order_by(*fields)
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
week_day
aggregate(args - *kwargs)
28. This query deletes all Entry objects with a pub_date year of 2005.
null
Entry.objects.filter(pub_date__year=2005).delete()
clear() method
Multi-table inheritance
29. Lookup type for date/datetime fields that finds a 'day of the week' match.
ordered
pk
week_day
Custom model methods
30. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
blank
month
save()
31. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
choices tuple
endswith
distinct()
filter
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
in_bulk(id_list)
blank
all()
relationship spanning
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.
when you add new apps to INSTALLED_APPS
unique
distinct()
exact
34. Lookup type that returns results with a case-insensitive start sequence.
Entry.objects.filter(pub_date__range=(start_date - end_date))
unique
pickling
istartswith
35. The database that will be used if this query is executed now
month
exclude(**kwargs)
default
db
36. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.
only(*fields)
filter(**kwargs)
count()
annotate(args - *kwargs)
37. 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.
Custom model methods
primary_key
in_bulk(id_list)
evaluation
38. Sometimes - the Django query syntax by itself can't easily express a complex WHERE clause. For these edge cases - Django provides this QuerySet modifier -- a hook for injecting specific clauses into the SQL generated by a QuerySet.
help_text
evaluation
select_related()
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
39. 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-many relationship through an intermediate model
through argument
year
filter(**kwargs)
40. 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.
Multi-table inheritance
delete()
pickling
filter(**kwargs)
41. Defined by a OneToOneField. You use it just like any other Field type: by including it as a class attribute of your model.
one-to-one relationship
Many-to-many relationship to self
QuerySet
MultipleObjectsReturned
42. Lookup type that tests for inclusion in a case-sensitive fashion.
startswith
select_related()
contains
Entry.objects.filter(pub_date__range=(start_date - end_date))
43. 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)
Model metadata
exact
filter(**kwargs)
F()
44. To activate your models
only(*fields)
delete()
Meta class
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
45. Lookup type that finds a case-sensitive regular expression match.
Entry.objects.filter(id__gt=4)
db
regex
id field
46. Lookup type that returns results in a given list.
Entry.objects.filter(pub_date__year=2007).update(headline='Everything is the same')
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
in
choices tuple
47. These are specified as keyword arguments to the QuerySet methods filter() - exclude() and get(). These take the form field__lookuptype=value .
Field lookups
filter
search
in_bulk(id_list)
48. 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.
iteration
filter(**kwargs)
select_related()
choices tuple
49. These methods are intended to do "table-wide" things.
values(*fields)
Manager methods
evaluation
Entry.objects.filter(id__gt=4)
50. 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.
filter(**kwargs)
choices
annotate(args - *kwargs)
Q()