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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. (1) These cannot be Python reserved words - because that would result in a Python syntax error. (2) These cannot contain more than one underscore in a row - due to the way Django's query lookup syntax works.






2. 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)






3. 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.






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






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






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






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






9. 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






10. 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.






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






12. To activate your models






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






14. 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.






15. 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.






16. Returns the object matching the given lookup parameters






17. When to run syncdb






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






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






20. Returns a ValuesQuerySet -- a QuerySet that returns dictionaries when used as an iterable - rather than model-instance objects.






21. 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






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






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






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






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






26. 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.






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






28. A Manager method that returns a new QuerySet containing objects that match the given lookup parameters.






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






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






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






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






33. 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.






34. 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.






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






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






37. 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






38. 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.






39. Conjuntion operator for Q objects.






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






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






42. 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.






43. 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.






44. 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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45. 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.






46. Negation operator for Q objects.






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






48. Fields are specified by these






49. 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






50. 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.