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






2. 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






3. 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






4. Disjunction operator for Q objects.






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






6. 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






7. 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.






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






9. Conjuntion operator for Q objects.






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






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






12. 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






13. 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.






14. Returns a copy of the current QuerySet (or QuerySet subclass you pass in). This can be useful in some situations where you might want to pass in either a model manager or a QuerySet and do further filtering on the result. You can safely call all() on






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






16. Returns True if the QuerySet contains any results - and False if not. This tries to perform the query in the simplest and fastest way possible - but it does execute nearly the same query. This means that calling this method on a queryset is faster th






17. 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.






18. 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.






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






20. 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






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






22. 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.






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


24. 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.






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






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






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






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






29. 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.






30. 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.






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






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






33. If True - this field is the primary key for the model.






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






35. 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






36. 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






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






38. 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.






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






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






41. This tells Django how to calculate the URL for an object. Django uses this in its admin interface - and any time it needs to figure out a URL for an object.






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






43. This is a criterion that narrow down a QuerySet based on given parameters.






44. 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.






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






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






47. 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.






48. 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.






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






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