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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. 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






2. 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.






3. 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.






4. If this option is True - Django will store empty values as NULL in the database. Default is False.






5. 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.






6. 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






7. Returns an integer representing the number of objects in the database matching the QuerySet. This never raises exceptions.






8. Lookup type that finds a case-insensitive regular expression match.






9. 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






10. Used to get a QuerySet for a model. This is called 'objects' by default.






11. Operator for comparing two model instances for equality. Behind the scenes - it compares the primary key values of two models.






12. True if the QuerySet has an order_by() clause or a default ordering on the model. False otherwise.






13. 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.






14. 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






15. Conjuntion operator for Q objects.






16. If this option is True - the field is allowed to be blank. Default is False.






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

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18. 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






19. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.






20. Lookup type that tests for inclusion in a case-sensitive fashion.






21. Keyword shortcut for looking up an object by primary key.






22. Lookup type for date/datetime fields that finds a 'day of the week' match.






23. This query finds all entries with an id greater than 4.






24. Lookup type that returns results greater than or equal to a given value.






25. Lookup type for date/datetime fields that finds an exact day match.






26. 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.






27. 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






28. 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






29. A convenience method for constructing an object and saving it all in one step.






30. 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.






31. A Q object that encapsulates queries for entries with a question value that starts with 'What' in a case-insensitive fashion.

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32. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.






33. Returns a new QuerySet that uses SELECT DISTINCT in its SQL query. This eliminates duplicate rows from the query results.






34. 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.






35. Lookup type that returns results greater than a given value.






36. 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






37. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12






38. 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.

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39. Lookup type that returns results less than or equal to a given value.






40. Lookup type that takes either True or False and corresponds to SQL queries of IS NULL and IS NOT NULL - respectively.






41. 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.






42. A Python "magic method" that returns a unicode "representation" of any object.






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.






44. Lookup type that returns results that fall into an inclusive date range.






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






46. 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.






47. Lookup type that returns results with a case-sensitive end sequence.






48. 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)






49. A convenience method for looking up an object with the given kwargs - creating one if necessary.






50. Lookup type that returns results with a case-insensitive start sequence.