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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. 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.






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






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






4. 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






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






6. 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.






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






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






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






10. 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.






11. 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()






12. 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.






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






14. 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.






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. 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.






17. 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)






18. 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.






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






20. Conjuntion operator for Q objects.






21. This gives your model metadata.






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






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






24. 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.






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






26. Disjunction operator for Q objects.






27. 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






28. 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






29. 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






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






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






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






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






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






36. 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






37. 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






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






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






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






41. 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






42. This query finds all entries between a start date of start_date and an end date of end_date.






43. 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.






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.


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






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






47. Lookup type that yields a case-insensitive match.






48. 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.






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






50. 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.