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






2. 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.






3. 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.






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






5. 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






6. This gives your model metadata.






7. 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






8. 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.






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






11. 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






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






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






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






15. 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.






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






17. 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.






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






19. 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






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






22. Negation operator for Q objects.






23. (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.






24. 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()






25. To activate your models






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






27. 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.






28. 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






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






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






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






32. 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






33. Conjuntion operator for Q objects.






34. 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.






35. 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.






36. When to run syncdb






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






38. Performs an SQL update query for the specified fields - and returns the number of rows affected. This method is applied instantly and the only restriction on the QuerySet that is updated is that it can only update columns in the model's main table. F






39. 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.






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

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






42. Lookup type for date/datetime fields that finds an exact month match. Takes an integer 1 (January) through 12






43. Lookup type that returns results greater than or equal to a given value.






44. 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






45. 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.






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






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






48. 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.






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






50. 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.