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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. 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.






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






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






4. 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()






5. 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






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






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






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






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






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

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12. Returns the most recent object in the table - by date - using the field_name provided as the date field.






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






14. If you pickle a QuerySet - this will force all the results to be loaded into memory prior to pickling. When you unpickle a QuerySet - it contains the results at the moment it was pickled - rather than the results that are currently in the database.






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






16. 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






17. Lookup type for date/datetime fields that finds an exact year match. Takes a four-digit year.






18. This represents a collection of objects from your database. It can have zero - one or many filters.






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






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






21. 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)






22. 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.






23. 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.






24. 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.






25. Lookup type that returns results with a case-insensitive end sequence.






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






27. 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






28. Negation operator for Q objects.






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






30. 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






31. 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.






32. This field is added automatically - but this behavior can be overridden






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






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






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






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






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






38. 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






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






40. 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.






41. 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






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






43. 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.






44. 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






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






47. To activate your models






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






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






50. These methods are intended to do "table-wide" things.