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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.
  • 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. 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)






2. 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






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






4. 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






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






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






7. 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.






8. 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.






9. 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






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






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






12. Here - you can't use add - create - or assignment (i.e. - beatles.members = [...]) to create relationships. You need to specify all the detail for the relationship required by the intermediate model.






13. Exception raised by get(**kwargs) if no items match the query.






14. 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.






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






16. 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.






17. 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






18. This method returns tuples of values when iterated over. Each tuple contains the value from the respective field passed into the call to this method -- so the first item is the first field - etc.






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






20. 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






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






22. 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.






23. 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






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






25. 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.






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






27. These are specified as keyword arguments to the QuerySet methods filter() - exclude() and get(). These take the form field__lookuptype=value .






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






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






30. 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.






31. 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.






32. 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.






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






34. 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.






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






36. A manager method that returns a new QuerySet containing objects that do not match the given lookup parameters.






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






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






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






40. 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.






41. Specifies the model that will be used to govern the many-to-many relationship. You can then put extra fields on the intermediate model. The intermediate model is associated with the ManyToManyField using this to point to the model that will act as an






42. 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






43. 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.






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






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






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






47. Disjunction operator for Q objects.






48. 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






49. Fields are specified by these






50. Negation operator for Q objects.