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. 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.






2. 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






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






5. 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






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






7. 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






8. 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.






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






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






11. 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






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






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






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






15. 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.






16. 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.






17. 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.






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






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






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


21. 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.






22. 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.






23. 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.






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






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.






26. 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






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






28. Fields are specified by these






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






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






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






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






33. 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






34. 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.






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






36. 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.






37. 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.






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






39. 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.






40. This query finds all entries with an id in the list [1 - 3 - 4]






41. Negation operator for Q objects.






42. 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)






43. This gives your model metadata.






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






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






46. 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






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






48. 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






49. Exception raised by get(**kwargs) if no items match the query.






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