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Django Queryset

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






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






3. 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.






4. Can be used to remove all many-to-many relationships for an instance






5. Exception raised by get(**kwargs) if more than one item matches the query.






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






7. a QuerySet can be sliced - using Python's array-slicing syntax.






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






9. If True - the table does not permit duplicate values for this field.






10. 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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11. Defined by a ManyToManyField. You use it just like any other Field type: by including it as a class attribute of your model.






12. 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.






13. Defined by a OneToOneField. You use it just like any other Field type: by including it as a class attribute of your model.






14. Conjuntion operator for Q objects.






15. This model method is used for updating a ManyToManyField.






16. 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()






17. 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






18. 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






19. 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.






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






21. 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






22. When to run syncdb






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






24. 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.






25. This model method saves a model instance to the database. This method has no return value.






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






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






28. Fields are specified by these






29. 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.






30. Manager method used to retrieve every object in a model.






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

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32. The default for this is the name of the child class followed by '_set'.






33. Each one of these is a Python class that subclasses django.db.models.Model. Each attribute of one of these represents a database field.






34. 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






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






36. This query deletes all Entry objects with a pub_date year of 2005.






37. 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.






38. The database that will be used if this query is executed now






39. Negation operator for Q objects.






40. This gives your model metadata.






41. These add custom "row-level" functionality to your objects. These act on a particular model instance.






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






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






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






45. Lookup type that returns results with a case-sensitive start sequence.






46. 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.






47. 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.






48. 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.






49. Lookup type that returns results in a given list.






50. 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