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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. 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






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






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






4. 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.






5. 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.






6. 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.






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






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






9. 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.






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






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






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






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






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






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






17. 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.






18. 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






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






20. 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.






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






22. Conjuntion operator for Q objects.






23. This gives your model metadata.






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






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






26. Performs an SQL delete query on all rows in the QuerySet. This method is applied instantly. You cannot call this method on a QuerySet that has had a slice taken or can otherwise no longer be filtered.






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






28. 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.






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






30. 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.






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






32. 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.






33. 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)






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






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






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






37. A Q object that encapsulates queries for entries with a question value that starts with 'What' in a case-insensitive fashion.

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38. 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()






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






40. This query updates all the headlines with pub_date in 2007 to read 'Everything is the same'.

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41. Negation operator for Q objects.






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






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






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






45. 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






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






47. 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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48. 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






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. 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.