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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. Lookup type that returns results less than a given value.
Entry.objects.filter(pub_date__range=(start_date - end_date))
values_list(*fields)
lt
class type
2. 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
many-to-one relationship
range
|
intermediate models
3. Each one of these is a Python class that subclasses django.db.models.Model. Each attribute of one of these represents a database field.
update(**kwargs)
model
filter(**kwargs)
isnull
4. This query uses an F object to increment the pingback count for every entry in the blog.
Warning
: Invalid argument supplied for foreach() in
/var/www/html/basicversity.com/show_quiz.php
on line
183
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
filter(**kwargs)
update(**kwargs)
F()
order_by(*fields)
6. If True - the table does not permit duplicate values for this field.
save()
pk
default
unique
7. Lookup type that yields a case-insensitive match.
intermediate models
iexact
primary_key
slicing
8. 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.
iregex
only(*fields)
OneToOneField
MultipleObjectsReturned
9. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.
distinct()
week_day
Field lookups
iexact
10. Lookup type that finds a case-insensitive regular expression match.
model
reverse()
default
iregex
11. If True - this field is the primary key for the model.
one-to-one relationship
OneToOneField
primary_key
clear() method
12. Conjuntion operator for Q objects.
one-to-one relationship
&
|
evaluation
13. 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
none()
Many-to-many relationship to self
unique
14. This gives your model metadata.
Meta class
Abstract base class
when you add new apps to INSTALLED_APPS
get(**kwargs)
15. The default for this is the name of the child class followed by '_set'.
iterator()
year
search
reverse name
16. Returns the most recent object in the table - by date - using the field_name provided as the date field.
latest(field_name=None)
__unicode__()
save()
iregex
17. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.
pk
exclude(**kwargs)
Proxy model
primary_key
18. 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.
Entry.objects.filter(id__in=[1 - 3 - 4])
through argument
exact
extra(select=None - where=None - params=None - tables=None - order_by=None - select_params=None)
19. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.
lte
defer(*fields)
isnull
DoesNotExist
20. 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
ManyToManyField
ordered
class type
range
21. This model method saves a model instance to the database. This method has no return value.
save()
many-to-many relationship
values_list(*fields)
choices tuple
22. 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
values(*fields)
|
choices tuple
through argument
23. 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
Multi-table inheritance
isnull
delete()
24. 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)
exclude(**kwargs)
month
isnull
25. 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.
iteration
Abstract base class
search
through argument
26. 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.
Entry.objects.all().update(n_pingbacks=F('n_pingbacks') + 1)
gt
update()
Entry.objects.filter(pub_date__year=2005).delete()
27. This class type is useful when you just want to use the parent class to hold information that you don't want to have to type out for each child model. This class isn't going to ever be used in isolation. When it is used as a base class for other mode
null
related_name
count()
Abstract base class
28. These are specified as keyword arguments to the QuerySet methods filter() - exclude() and get(). These take the form field__lookuptype=value .
Field lookups
relationship spanning
model
one-to-one relationship
29. When to run syncdb
values(*fields)
filter chaining
filter
when you add new apps to INSTALLED_APPS
30. 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.
dates(field - kind - order='ASC')
range
order_by(*fields)
many-to-one relationship
31. These add custom "row-level" functionality to your objects. These act on a particular model instance.
through argument
evaluation
Custom model methods
DoesNotExist
32. 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
Restrictions on field names
null
exists()
when you add new apps to INSTALLED_APPS
33. Negation operator for Q objects.
Multi-table inheritance
search
~
create(**kwargs)
34. This is a criterion that narrow down a QuerySet based on given parameters.
filter
distinct()
week_day
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
35. 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
only(*fields)
Proxy model
Abstract base class
endswith
36. 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()
null
get_absolute_url()
Proxy model
37. Lookup type that returns results in a given list.
Entry.objects.filter(id__gt=4)
get(**kwargs)
in
filter(**kwargs)
38. This field is added automatically - but this behavior can be overridden
primary_key
id field
ForeignKey
Multi-table inheritance
39. 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.
ForeignKey
get_absolute_url()
edit your settings file and change the INSTALLED_APPS setting to add the name of the module that contains your models.py.
F()
40. This query finds all entries with an id in the list [1 - 3 - 4]
Field lookups
startswith
lt
Entry.objects.filter(id__in=[1 - 3 - 4])
41. Manager method used to retrieve every object in a model.
filter chaining
year
many-to-one relationship
all()
42. Lookup type that returns results with a case-sensitive start sequence.
pickling
startswith
order_by(*fields)
ordered
43. 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()
distinct()
startswith
pk
44. 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
lt
order_by(*fields)
get_or_create(**kwargs)
45. 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)
slicing
one-to-one relationship
Entry.objects.filter(pub_date__year=2005).delete()
46. Lookup type that returns results greater than or equal to a given value.
iendswith
gte
Manager
contains
47. Lookup type that returns results with a case-insensitive end sequence.
filter
iterator()
latest(field_name=None)
iendswith
48. A convenience method for constructing an object and saving it all in one step.
values(*fields)
iteration
create(**kwargs)
get(**kwargs)
49. This method immediately deletes the object and has no return value.
in
get_or_create(**kwargs)
delete()
many-to-many relationship
50. 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.
all()
get(**kwargs)
distinct()
evaluation