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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. 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.






2. Disjunction operator for Q objects.






3. 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






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






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






6. 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






7. 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






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






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






10. 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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11. 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






12. 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()






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






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






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






16. 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.






17. 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






18. To activate your models






19. Exception raised by get(**kwargs) if more than one item matches the query.






20. 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






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






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






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






24. Lookup type that returns results less than or equal to a given value.






25. 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)






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






27. 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.






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






29. 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.






30. 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.






31. 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






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






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






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






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






36. 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






37. Fields are specified by these






38. 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.






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






40. This field is added automatically - but this behavior can be overridden






41. Lookup type that returns results with a case-sensitive start sequence.






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






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






44. 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.






45. 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.






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

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47. 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.






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






49. Conjuntion operator for Q objects.






50. 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