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Django Queryset

Subject : it-skills
Instructions:
  • Answer 50 questions in 15 minutes.
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  • Match each statement with the correct term.
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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. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.






2. 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.






3. 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






4. 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






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






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






7. 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.






8. (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.






9. 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






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






11. 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.






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






13. 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.






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






15. 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.






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






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






18. 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






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






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






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






22. 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.






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






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






25. 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






26. Disjunction operator for Q objects.






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






28. 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






29. Lookup type for date/datetime fields that finds an exact day match.






30. 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.






31. 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






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






33. 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.






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






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






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






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






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






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






40. This method is for controlling which database the QuerySet will be evaluated against if you are using more than one database. The only argument this method takes is the alias of a database - as defined in DATABASES.






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






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






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






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






45. 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






46. 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.






47. 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.






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






49. 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.






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