Test your basic knowledge |

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. 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






2. 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.






3. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.






4. 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.






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






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






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






8. A Q object that asks for entries with a question value that start with 'Who' or do not have a publication date of 2005.

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9. 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.






10. These are specified as keyword arguments to the QuerySet methods filter() - exclude() and get(). These take the form field__lookuptype=value .






11. 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.






12. Lookup type that finds a case-sensitive regular expression match.






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






14. 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.






15. Here - you can't use add - create - or assignment (i.e. - beatles.members = [...]) to create relationships. You need to specify all the detail for the relationship required by the intermediate model.






16. 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






17. This style of inheritanc is useful when you're subclassing an existing model (perhaps something from another application entirely) and want each model to have its own database table. Here - each model in the hierarchy is a model all by itself.






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






19. This method immediately deletes the object and has no return value.






20. 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






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






22. 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






23. 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.






24. 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.






25. 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.






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






27. Defines a many-to-one relationship. ou use it just like any other Field type: by including it as a class attribute of your model.






28. 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






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






30. When to run syncdb






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






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






33. 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.






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






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






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






37. Lookup type that returns results less than a given value.






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






39. Fields are specified by these






40. If you are using this attribute on a ForeignKey or ManyToManyField - you must always specify a unique reverse name for the field.






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






42. 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






43. Disjunction operator for Q objects.






44. 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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45. Lookup type that yields a case-insensitive match.






46. 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.






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






48. 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.






49. This gives your model metadata.






50. Returns a new QuerySet containing objects that match the given lookup parameters.