Untitled

(venv) D:\nauka\coderslab\sierpien\ONL_PYT_W_29_podstawy_django-main\project>python manage.py migrate
Operations to perform:
  Apply all migrations: admin, auth, contenttypes, exercises_app, football, sessions
Running migrations:
  Applying exercises_app.0009_album_band... OK

(venv) D:\nauka\coderslab\sierpien\ONL_PYT_W_29_podstawy_django-main\project>python manage.py shell
Python 3.9.0 (tags/v3.9.0:9cf6752, Oct  5 2020, 15:34:40) [MSC v.1927 64 bit (AMD64)]
Type 'copyright', 'credits' or 'license' for more information
IPython 8.14.0 -- An enhanced Interactive Python. Type '?' for help.

In [1]: from exercises_app.models import Album, Band

In [2]: bands = Band.objects.all()

In [3]: Album.objects.create(title='sample3', year=1990, rate=5, band=bands[1])
Out[3]: <Album: Album object (1)>

In [4]: Album.objects.create(title='sample4', year=1990, rate=5, band=bands[0])
Out[4]: <Album: Album object (2)>

In [5]: Album.objects.create(title='sample5', year=1994, rate=2, band=bands[2])
Out[5]: <Album: Album object (3)>

In [6]: Album.objects.create(title='sample 6', year=1996, rate=5, band=bands[2])
Out[6]: <Album: Album object (4)>

In [7]: bands = Band.objects.all()

In [8]: print(dir(bands[2]))
['DoesNotExist', 'MultipleObjectsReturned', '__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__
', '__getattribute__', '__getstate__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__',
 '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__setstate__', '__sizeof__', '__str__', '__subclasshook__', '__wea
kref__', '_check_column_name_clashes', '_check_constraints', '_check_default_pk', '_check_field_name_clashes', '_check_fields', '_check_i
d_field', '_check_index_together', '_check_indexes', '_check_local_fields', '_check_long_column_names', '_check_m2m_through_same_relation
ship', '_check_managers', '_check_model', '_check_model_name_db_lookup_clashes', '_check_ordering', '_check_property_name_related_field_a
ccessor_clashes', '_check_single_primary_key', '_check_swappable', '_check_unique_together', '_do_insert', '_do_update', '_get_FIELD_disp
lay', '_get_expr_references', '_get_next_or_previous_by_FIELD', '_get_next_or_previous_in_order', '_get_pk_val', '_get_unique_checks', '_
meta', '_perform_date_checks', '_perform_unique_checks', '_prepare_related_fields_for_save', '_save_parents', '_save_table', '_set_pk_val
', '_state', 'album_set', 'check', 'clean', 'clean_fields', 'date_error_message', 'delete', 'from_db', 'full_clean', 'genre', 'get_deferr
ed_fields', 'get_genre_display', 'id', 'name', 'objects', 'pk', 'prepare_database_save', 'refresh_from_db', 'save', 'save_base', 'seriali
zable_value', 'still_active', 'unique_error_message', 'validate_unique', 'year']

In [9]: print(bands[2].album_set)
exercises_app.Album.None

In [10]: print(bands[2].album_set.get())
---------------------------------------------------------------------------
MultipleObjectsReturned                   Traceback (most recent call last)
Cell In[10], line 1
----> 1 print(bands[2].album_set.get())

File D:\nauka\coderslab\sierpien\ONL_PYT_W_29_podstawy_django-main\project\venv\lib\site-packages\django\db\models\manager.py:85, in Base
Manager._get_queryset_methods.<locals>.create_method.<locals>.manager_method(self, *args, **kwargs)
     84 def manager_method(self, *args, **kwargs):
---> 85     return getattr(self.get_queryset(), name)(*args, **kwargs)

File D:\nauka\coderslab\sierpien\ONL_PYT_W_29_podstawy_django-main\project\venv\lib\site-packages\django\db\models\query.py:443, in Query
Set.get(self, *args, **kwargs)
    438 if not num:
    439     raise self.model.DoesNotExist(
    440         "%s matching query does not exist." %
    441         self.model._meta.object_name
    442     )
--> 443 raise self.model.MultipleObjectsReturned(
    444     'get() returned more than one %s -- it returned %s!' % (
    445         self.model._meta.object_name,
    446         num if not limit or num < limit else 'more than %s' % (limit - 1),
    447     )
    448 )

MultipleObjectsReturned: get() returned more than one Album -- it returned 2!

In [11]: bands[2].album_set.get()
---------------------------------------------------------------------------
MultipleObjectsReturned                   Traceback (most recent call last)
Cell In[11], line 1
----> 1 bands[2].album_set.get()

File D:\nauka\coderslab\sierpien\ONL_PYT_W_29_podstawy_django-main\project\venv\lib\site-packages\django\db\models\manager.py:85, in Base
Manager._get_queryset_methods.<locals>.create_method.<locals>.manager_method(self, *args, **kwargs)
     84 def manager_method(self, *args, **kwargs):
---> 85     return getattr(self.get_queryset(), name)(*args, **kwargs)

File D:\nauka\coderslab\sierpien\ONL_PYT_W_29_podstawy_django-main\project\venv\lib\site-packages\django\db\models\query.py:443, in Query
Set.get(self, *args, **kwargs)
    438 if not num:
    439     raise self.model.DoesNotExist(
    440         "%s matching query does not exist." %
    441         self.model._meta.object_name
    442     )
--> 443 raise self.model.MultipleObjectsReturned(
    444     'get() returned more than one %s -- it returned %s!' % (
    445         self.model._meta.object_name,
    446         num if not limit or num < limit else 'more than %s' % (limit - 1),
    447     )
    448 )

MultipleObjectsReturned: get() returned more than one Album -- it returned 2!

In [12]: bands[2].album_set.all()
Out[12]: <QuerySet [<Album: Album object (3)>, <Album: Album object (4)>]>

In [13]: [print(album.title) for album in bands[2].album_set.all()]
sample5
sample 6
Out[13]: [None, None]