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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 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.






2. 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.






3. Evaluates the QuerySet (by performing the query) and returns an iterator over the results. A QuerySet typically caches its results internally so that repeated evaluations do not result in additional queries; this method will instead read results dire






4. 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.






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






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






7. 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.






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






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






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






12. 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






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






14. 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.






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. Fields are specified by these






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






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






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






20. 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.






21. 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.






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. 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






24. 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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25. 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.






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






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






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






29. 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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30. 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






31. When to run syncdb






32. This gives your model metadata.






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






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






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






36. 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()






37. (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.






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






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






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






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






42. A QuerySet is iterable - and it executes its database query the first time you iterate over it.






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






44. 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)






45. To activate your models






46. 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






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






48. 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.






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






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