Django

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Ticket #6095: 6095-beta-06.diff

File 6095-beta-06.diff, 27.5 kB (added by floguy, 9 months ago)

Added/reworded lots of the comments to the m2m_manual doctests (maybe these tests need a rename, hmmm), and fixed some issues with the .diff that prevented parts from showing up last time.

  • a/AUTHORS

    old new  
    133133    Afonso Fernández Nogueira <fonzzo.django@gmail.com> 
    134134    Matthew Flanagan <http://wadofstuff.blogspot.com> 
    135135    Eric Floehr <eric@intellovations.com> 
     136    Eric Florenzano <floguy@gmail.com> 
    136137    Vincent Foley <vfoleybourgon@yahoo.ca> 
    137138    Rudolph Froger <rfroger@estrate.nl> 
    138139    Jorge Gajon <gajon@gajon.org> 
  • a/django/core/management/sql.py

    old new  
    352352    qn = connection.ops.quote_name 
    353353    inline_references = connection.features.inline_fk_references 
    354354    for f in opts.many_to_many: 
    355         if not isinstance(f.rel, generic.GenericRel)
     355        if not isinstance(f.rel, generic.GenericRel) and f.creates_table
    356356            tablespace = f.db_tablespace or opts.db_tablespace 
    357357            if tablespace and connection.features.supports_tablespaces and connection.features.autoindexes_primary_keys: 
    358358                tablespace_sql = ' ' + connection.ops.tablespace_sql(tablespace, inline=True) 
  • a/django/core/management/validation.py

    old new  
    104104                        if r.get_accessor_name() == rel_query_name: 
    105105                            e.add(opts, "Reverse query name for field '%s' clashes with related field '%s.%s'. Add a related_name argument to the definition for '%s'." % (f.name, rel_opts.object_name, r.get_accessor_name(), f.name)) 
    106106 
     107        seen_intermediary_signatures = [] 
     108 
    107109        for i, f in enumerate(opts.many_to_many): 
    108110            # Check to see if the related m2m field will clash with any 
    109111            # existing fields, m2m fields, m2m related objects or related objects 
     
    113115                # so skip the next section 
    114116                if isinstance(f.rel.to, (str, unicode)): 
    115117                    continue 
     118            if hasattr(f.rel, 'through') and f.rel.through != None: 
     119                intermediary_model = None 
     120                for model in models.get_models(): 
     121                    if model._meta.module_name == f.rel.through.lower(): 
     122                        intermediary_model = model 
     123                if intermediary_model == None: 
     124                    e.add(opts, "%s has a manually-defined m2m relationship through a model (%s) which does not exist." % (f.name, f.rel.through)) 
     125                else: 
     126                    signature = (f.rel.to, cls, intermediary_model) 
     127                    if signature in seen_intermediary_signatures: 
     128                        e.add(opts, "%s has two manually-defined m2m relationships through the same model (%s), which is not possible.  Please use a field on your intermediary model instead." % (cls._meta.object_name, intermediary_model._meta.object_name)) 
     129                    else: 
     130                        seen_intermediary_signatures.append(signature) 
     131                    seen_related_fk, seen_this_fk = False, False 
     132                    for field in intermediary_model._meta.fields: 
     133                        if field.rel: 
     134                            if field.rel.to == f.rel.to: 
     135                                seen_related_fk = True 
     136                            elif field.rel.to == cls: 
     137                                seen_this_fk = True 
     138                    if not seen_related_fk or not seen_this_fk: 
     139                        e.add(opts, "%s has a manually-defined m2m relationship through a model (%s) which does not have foreign keys to %s and %s" % (f.name, f.rel.through, f.rel.to._meta.object_name, cls._meta.object_name)) 
    116140 
    117141            rel_opts = f.rel.to._meta 
    118142            rel_name = RelatedObject(f.rel.to, cls, f).get_accessor_name() 
  • a/django/db/models/fields/related.py

    old new  
    1010from django import oldforms 
    1111from django import newforms as forms 
    1212from django.dispatch import dispatcher 
     13from new import instancemethod 
    1314 
    1415try: 
    1516    set 
     
    262263            manager.clear() 
    263264        manager.add(*value) 
    264265 
    265 def create_many_related_manager(superclass): 
     266def create_many_related_manager(superclass, through=False): 
    266267    """Creates a manager that subclasses 'superclass' (which is a Manager) 
    267268    and adds behavior for many-to-many related objects.""" 
    268269    class ManyRelatedManager(superclass): 
    269270        def __init__(self, model=None, core_filters=None, instance=None, symmetrical=None, 
    270                 join_table=None, source_col_name=None, target_col_name=None): 
     271                join_table=None, source_col_name=None, target_col_name=None,  
     272                through=None): 
    271273            super(ManyRelatedManager, self).__init__() 
    272274            self.core_filters = core_filters 
    273275            self.model = model 
     
    276278            self.join_table = join_table 
    277279            self.source_col_name = source_col_name 
    278280            self.target_col_name = target_col_name 
     281            self.through = through 
    279282            self._pk_val = self.instance._get_pk_val() 
    280283            if self._pk_val is None: 
    281284                raise ValueError("%r instance needs to have a primary key value before a many-to-many relationship can be used." % model) 
     
    283286        def get_query_set(self): 
    284287            return superclass.get_query_set(self).filter(**(self.core_filters)) 
    285288 
    286         def add(self, *objs): 
    287             self._add_items(self.source_col_name, self.target_col_name, *objs) 
    288  
    289             # If this is a symmetrical m2m relation to self, add the mirror entry in the m2m table 
    290             if self.symmetrical: 
    291                 self._add_items(self.target_col_name, self.source_col_name, *objs) 
    292         add.alters_data = True 
    293  
    294         def remove(self, *objs): 
    295             self._remove_items(self.source_col_name, self.target_col_name, *objs) 
    296  
    297             # If this is a symmetrical m2m relation to self, remove the mirror entry in the m2m table 
    298             if self.symmetrical: 
    299                 self._remove_items(self.target_col_name, self.source_col_name, *objs) 
    300         remove.alters_data = True 
    301  
    302289        def clear(self): 
    303290            self._clear_items(self.source_col_name) 
    304291 
     
    375362                [self._pk_val]) 
    376363            transaction.commit_unless_managed() 
    377364 
     365    def add(self, *objs): 
     366        self._add_items(self.source_col_name, self.target_col_name, *objs) 
     367        # If this is a symmetrical m2m relation to self, add the mirror entry in the m2m table 
     368        if self.symmetrical: 
     369            self._add_items(self.target_col_name, self.source_col_name, *objs) 
     370    add.alters_data = True 
     371 
     372    def remove(self, *objs): 
     373        self._remove_items(self.source_col_name, self.target_col_name, *objs) 
     374        # If this is a symmetrical m2m relation to self, remove the mirror entry in the m2m table 
     375        if self.symmetrical: 
     376            self._remove_items(self.target_col_name, self.source_col_name, *objs) 
     377    remove.alters_data = True 
     378 
     379    if not through: 
     380        ManyRelatedManager.add = instancemethod(add, None, ManyRelatedManager) 
     381        ManyRelatedManager.remove = instancemethod(remove, None, ManyRelatedManager) 
     382 
    378383    return ManyRelatedManager 
    379384 
    380385class ManyRelatedObjectsDescriptor(object): 
     
    395400        # model's default manager. 
    396401        rel_model = self.related.model 
    397402        superclass = rel_model._default_manager.__class__ 
    398         RelatedManager = create_many_related_manager(superclass
     403        RelatedManager = create_many_related_manager(superclass, self.related.field.rel.through
    399404 
    400405        qn = connection.ops.quote_name 
    401406        manager = RelatedManager( 
     
    405410            symmetrical=False, 
    406411            join_table=qn(self.related.field.m2m_db_table()), 
    407412            source_col_name=qn(self.related.field.m2m_reverse_name()), 
    408             target_col_name=qn(self.related.field.m2m_column_name()) 
     413            target_col_name=qn(self.related.field.m2m_column_name()), 
     414            through=self.related.field.rel.through 
    409415        ) 
    410416 
    411417        return manager 
     
    414420        if instance is None: 
    415421            raise AttributeError, "Manager must be accessed via instance" 
    416422 
     423        through = getattr(self.related.field.rel, 'through', None) 
     424        if through: 
     425            raise AttributeError, "Cannot set values on a ManyToManyField which specifies a through model.  Use %s's Manager instead." % through 
     426         
    417427        manager = self.__get__(instance) 
    418428        manager.clear() 
    419429        manager.add(*value) 
     
    436446        # model's default manager. 
    437447        rel_model=self.field.rel.to 
    438448        superclass = rel_model._default_manager.__class__ 
    439         RelatedManager = create_many_related_manager(superclass
     449        RelatedManager = create_many_related_manager(superclass, self.field.rel.through
    440450 
    441451        qn = connection.ops.quote_name 
    442452        manager = RelatedManager( 
     
    446456            symmetrical=(self.field.rel.symmetrical and instance.__class__ == rel_model), 
    447457            join_table=qn(self.field.m2m_db_table()), 
    448458            source_col_name=qn(self.field.m2m_column_name()), 
    449             target_col_name=qn(self.field.m2m_reverse_name()) 
     459            target_col_name=qn(self.field.m2m_reverse_name()), 
     460            through=self.field.rel.through 
    450461        ) 
    451462 
    452463        return manager 
     
    455466        if instance is None: 
    456467            raise AttributeError, "Manager must be accessed via instance" 
    457468 
     469        through = getattr(self.field.rel, 'through', None) 
     470        if through: 
     471            raise AttributeError, "Cannot set values on a ManyToManyField which specifies a through model.  Use %s's Manager instead." % through 
     472 
    458473        manager = self.__get__(instance) 
    459474        manager.clear() 
    460475        manager.add(*value) 
     
    648663            filter_interface=kwargs.pop('filter_interface', None), 
    649664            limit_choices_to=kwargs.pop('limit_choices_to', None), 
    650665            raw_id_admin=kwargs.pop('raw_id_admin', False), 
    651             symmetrical=kwargs.pop('symmetrical', True)) 
     666            symmetrical=kwargs.pop('symmetrical', True), 
     667            through=kwargs.pop('through', None)) 
    652668        self.db_table = kwargs.pop('db_table', None) 
     669        if kwargs['rel'].through: 
     670            self.creates_table = False 
     671            assert not self.db_table, "Cannot specify a db_table if an intermediary model is used."  
     672        else: 
     673            self.creates_table = True 
    653674        if kwargs["rel"].raw_id_admin: 
    654675            kwargs.setdefault("validator_list", []).append(self.isValidIDList) 
    655676        Field.__init__(self, **kwargs) 
     
    672693 
    673694    def _get_m2m_db_table(self, opts): 
    674695        "Function that can be curried to provide the m2m table name for this relation" 
    675         if self.db_table: 
     696        if self.rel.through != None:  
     697            return get_model(opts.app_label, self.rel.through)._meta.db_table 
     698        elif self.db_table: 
    676699            return self.db_table 
    677700        else: 
    678701            return '%s_%s' % (opts.db_table, self.name) 
     
    680703    def _get_m2m_column_name(self, related): 
    681704        "Function that can be curried to provide the source column name for the m2m table" 
    682705        # If this is an m2m relation to self, avoid the inevitable name clash 
    683         if related.model == related.parent_model: 
     706        if self.rel.through != None: 
     707            field = related.model._meta.get_related_object(self.rel.through).field 
     708            attname, column = field.get_attname_column()  
     709            return column  
     710        elif related.model == related.parent_model: 
    684711            return 'from_' + related.model._meta.object_name.lower() + '_id' 
    685712        else: 
    686713            return related.model._meta.object_name.lower() + '_id' 
     
    688715    def _get_m2m_reverse_name(self, related): 
    689716        "Function that can be curried to provide the related column name for the m2m table" 
    690717        # If this is an m2m relation to self, avoid the inevitable name clash 
    691         if related.model == related.parent_model: 
     718        if self.rel.through != None: 
     719            field = related.parent_model._meta.get_related_object(self.rel.through).field 
     720            attname, column = field.get_attname_column()  
     721            return column 
     722        elif related.model == related.parent_model: 
    692723            return 'to_' + related.parent_model._meta.object_name.lower() + '_id' 
    693724        else: 
    694725            return related.parent_model._meta.object_name.lower() + '_id' 
     
    809840 
    810841class ManyToManyRel(object): 
    811842    def __init__(self, to, num_in_admin=0, related_name=None, 
    812         filter_interface=None, limit_choices_to=None, raw_id_admin=False, symmetrical=True): 
     843        filter_interface=None, limit_choices_to=None, raw_id_admin=False, symmetrical=True, 
     844        through = None): 
    813845        self.to = to 
    814846        self.num_in_admin = num_in_admin 
    815847        self.related_name = related_name 
     
    821853        self.raw_id_admin = raw_id_admin 
    822854        self.symmetrical = symmetrical 
    823855        self.multiple = True 
     856        self.through = through 
    824857 
    825858        assert not (self.raw_id_admin and self.filter_interface), "ManyToManyRels may not use both raw_id_admin and filter_interface" 
  • a/django/db/models/options.py

    old new  
    22from django.db.models.related import RelatedObject 
    33from django.db.models.fields.related import ManyToManyRel 
    44from django.db.models.fields import AutoField, FieldDoesNotExist 
    5 from django.db.models.loading import get_models, app_cache_ready 
     5from django.db.models.loading import get_models, get_model, app_cache_ready 
    66from django.db.models.query import orderlist2sql 
    77from django.db.models import Manager 
    88from django.utils.translation import activate, deactivate_all, get_language, string_concat 
     
    162162            follow = self.get_follow() 
    163163        return [f for f in self.get_all_related_objects() if follow.get(f.name, None)] 
    164164 
     165    def get_related_object(self, from_model): 
     166        "Gets the RelatedObject which links from from_model to this model." 
     167        if isinstance(from_model, str): 
     168            from_model = get_model(self.app_label, from_model) 
     169        for related_object in self.get_all_related_objects(): 
     170            if related_object.model == from_model: 
     171                return related_object 
     172        return None 
     173 
    165174    def get_data_holders(self, follow=None): 
    166175        if follow == None: 
    167176            follow = self.get_follow() 
  • a/tests/modeltests/invalid_models/models.py

    old new  
    111111class MissingRelations(models.Model): 
    112112    rel1 = models.ForeignKey("Rel1") 
    113113    rel2 = models.ManyToManyField("Rel2") 
     114     
     115class MissingManualM2MModel(models.Model): 
     116    name = models.CharField(max_length=5) 
     117    missing_m2m = models.ManyToManyField(Model, through="MissingM2MModel") 
     118     
     119class Person(models.Model): 
     120    name = models.CharField(max_length=5) 
     121 
     122class Group(models.Model): 
     123    name = models.CharField(max_length=5) 
     124    primary = models.ManyToManyField(Person, through="Membership", related_name="primary") 
     125    secondary = models.ManyToManyField(Person, through="Membership", related_name="secondary") 
     126 
     127class GroupTwo(models.Model): 
     128    name = models.CharField(max_length=5) 
     129    primary = models.ManyToManyField(Person, through="Membership") 
     130    secondary = models.ManyToManyField(Group, through="MembershipMissingFK") 
     131 
     132class Membership(models.Model): 
     133    person = models.ForeignKey(Person) 
     134    group = models.ForeignKey(Group) 
     135    not_default_or_null = models.CharField(max_length=5) 
     136 
     137class MembershipMissingFK(models.Model): 
     138    person = models.ForeignKey(Person) 
    114139 
    115140model_errors = """invalid_models.fielderrors: "charfield": CharFields require a "max_length" attribute. 
    116141invalid_models.fielderrors: "decimalfield": DecimalFields require a "decimal_places" attribute. 
     
    197222invalid_models.selfclashm2m: Reverse query name for m2m field 'm2m_4' clashes with field 'SelfClashM2M.selfclashm2m'. Add a related_name argument to the definition for 'm2m_4'. 
    198223invalid_models.missingrelations: 'rel2' has m2m relation with model Rel2, which has not been installed 
    199224invalid_models.missingrelations: 'rel1' has relation with model Rel1, which has not been installed 
     225invalid_models.group: Group has two manually-defined m2m relationships through the same model (Membership), which is not possible.  Please use a field on your intermediary model instead. 
     226invalid_models.missingmanualm2mmodel: missing_m2m has a manually-defined m2m relationship through a model (MissingM2MModel) which does not exist. 
     227invalid_models.grouptwo: primary has a manually-defined m2m relationship through a model (Membership) which does not have foreign keys to Person and GroupTwo 
     228invalid_models.grouptwo: secondary has a manually-defined m2m relationship through a model (MembershipMissingFK) which does not have foreign keys to Group and GroupTwo 
    200229""" 
  • /dev/null

    old new  
     1from django.db import models 
     2from datetime import datetime 
     3 
     4# M2M described on one of the models 
     5class Person(models.Model): 
     6    name = models.CharField(max_length=128) 
     7 
     8    def __unicode__(self): 
     9        return self.name 
     10 
     11class Group(models.Model): 
     12    name = models.CharField(max_length=128) 
     13    members = models.ManyToManyField(Person, through='Membership') 
     14    custom_members = models.ManyToManyField(Person, through='CustomMembership', related_name="custom") 
     15    nodefaultsnonulls = models.ManyToManyField(Person, through='TestNoDefaultsOrNulls', related_name="testnodefaultsnonulls") 
     16     
     17    def __unicode__(self): 
     18        return self.name 
     19 
     20class Membership(models.Model): 
     21    person = models.ForeignKey(Person) 
     22    group = models.ForeignKey(Group) 
     23    date_joined = models.DateTimeField(default=datetime.now) 
     24    invite_reason = models.CharField(max_length=64, null=True) 
     25     
     26    def __unicode__(self): 
     27        return "%s is a member of %s" % (self.person.name, self.group.name) 
     28 
     29class CustomMembership(models.Model): 
     30    person = models.ForeignKey(Person, db_column="custom_person_column", related_name="custom_person_related_name") 
     31    group = models.ForeignKey(Group) 
     32    weird_fk = models.ForeignKey(Membership, null=True) 
     33    date_joined = models.DateTimeField(default=datetime.now) 
     34     
     35    def __unicode__(self): 
     36        return "%s is a member of %s" % (self.person.name, self.group.name) 
     37     
     38    class Meta: 
     39        db_table = "test_table" 
     40 
     41class TestNoDefaultsOrNulls(models.Model): 
     42    person = models.ForeignKey(Person) 
     43    group = models.ForeignKey(Group) 
     44    nodefaultnonull = models.CharField(max_length=5) 
     45 
     46__test__ = {'API_TESTS':""" 
     47>>> from datetime import datetime 
     48 
     49### Creation and Saving Tests ### 
     50 
     51>>> bob = Person.objects.create(name = 'Bob') 
     52>>> jim = Person.objects.create(name = 'Jim') 
     53>>> jane = Person.objects.create(name = 'Jane') 
     54>>> rock = Group.objects.create(name = 'Rock') 
     55>>> roll = Group.objects.create(name = 'Roll') 
     56 
     57# We start out by making sure that the Group 'rock' has no members. 
     58>>> rock.members.all() 
     59[] 
     60 
     61# To make Jim a member of Group Rock, simply create a Membership object. 
     62>>> m1 = Membership.objects.create(person = jim, group = rock) 
     63 
     64# We can do the same for Jane and Rock. 
     65>>> m2 = Membership.objects.create(person = jane, group = rock) 
     66 
     67# Let's check to make sure that it worked.  Jane and Jim should be members of Rock. 
     68>>> rock.members.all() 
     69[<Person: Jim>, <Person: Jane>] 
     70 
     71# Now we can add a bunch more Membership objects to test with. 
     72>>> m3 = Membership.objects.create(person = bob, group = roll) 
     73>>> m4 = Membership.objects.create(person = jim, group = roll) 
     74>>> m5 = Membership.objects.create(person = jane, group = roll) 
     75 
     76# We can get Jim's Group membership as with any ForeignKey. 
     77>>> jim.group_set.all() 
     78[<Group: Rock>, <Group: Roll>] 
     79 
     80# Querying the intermediary model works like normal.   
     81# In this case we get Jane's membership to Rock. 
     82>>> m = Membership.objects.get(person = jane, group = rock) 
     83>>> m 
     84<Membership: Jane is a member of Rock> 
     85 
     86# Now we set some date_joined dates for further testing. 
     87>>> m2.invite_reason = "She was just awesome." 
     88>>> m2.date_joined = datetime(2006, 1, 1) 
     89>>> m2.save() 
     90 
     91>>> m5.date_joined = datetime(2004, 1, 1) 
     92>>> m5.save() 
     93 
     94>>> m3.date_joined = datetime(2004, 1, 1) 
     95>>> m3.save() 
     96 
     97# It's not only get that works.  Filter works like normal as well. 
     98>>> Membership.objects.filter(person = jim) 
     99[<Membership: Jim is a member of Rock>, <Membership: Jim is a member of Roll>] 
     100 
     101 
     102### Forward Descriptors Tests ### 
     103 
     104# Due to complications with adding via an intermediary model, the add method is 
     105# not provided. 
     106>>> rock.members.add(bob) 
     107Traceback (most recent call last): 
     108... 
     109AttributeError: 'ManyRelatedManager' object has no attribute 'add' 
     110 
     111# Remove has similar complications, and is not provided either. 
     112>>> rock.members.remove(jim) 
     113Traceback (most recent call last): 
     114... 
     115AttributeError: 'ManyRelatedManager' object has no attribute 'remove' 
     116 
     117# Here we back up the list of all members of Rock. 
     118>>> backup = list(rock.members.all()) 
     119# ...and we verify that it has worked. 
     120>>> backup 
     121[<Person: Jim>, <Person: Jane>] 
     122 
     123# The clear function should still work. 
     124>>> rock.members.clear() 
     125# Now there will be no members of Rock. 
     126>>> rock.members.all() 
     127[] 
     128 
     129# Assignment should not work with models specifying a through model for many of 
     130# the same reasons as adding. 
     131>>> rock.members = backup 
     132Traceback (most recent call last): 
     133... 
     134AttributeError: Cannot set values on a ManyToManyField which specifies a through model.  Use Membership's Manager instead. 
     135 
     136# Let's re-save those instances that we've cleared. 
     137>>> m1.save() 
     138>>> m2.save() 
     139 
     140# Verifying that those instances were re-saved successfully. 
     141>>> rock.members.all() 
     142[<Person: Jim>, <Person: Jane>] 
     143 
     144 
     145### Reverse Descriptors Tests ### 
     146 
     147# Due to complications with adding via an intermediary model, the add method is 
     148# not provided. 
     149>>> bob.group_set.add(rock) 
     150Traceback (most recent call last): 
     151... 
     152AttributeError: 'ManyRelatedManager' object has no attribute 'add' 
     153 
     154# Remove has similar complications, and is not provided either. 
     155>>> jim.group_set.remove(rock) 
     156Traceback (most recent call last): 
     157... 
     158AttributeError: 'ManyRelatedManager' object has no attribute 'remove' 
     159 
     160# Here we back up the list of all of Jim's groups. 
     161>>> backup = list(jim.group_set.all()) 
     162>>> backup 
     163[<Group: Rock>, <Group: Roll>] 
     164 
     165# The clear function should still work. 
     166>>> jim.group_set.clear() 
     167# Now Jim will be in no groups. 
     168>>> jim.group_set.all() 
     169[] 
     170 
     171# Assignment should not work with models specifying a through model for many of 
     172# the same reasons as adding. 
     173>>> jim.group_set = backup 
     174Traceback (most recent call last): 
     175... 
     176AttributeError: Cannot set values on a ManyToManyField which specifies a through model.  Use Membership's Manager instead. 
     177 
     178# Let's re-save those instances that we've cleared. 
     179>>> m1.save() 
     180>>> m4.save() 
     181 
     182# Verifying that those instances were re-saved successfully. 
     183>>> jim.group_set.all() 
     184[<Group: Rock>, <Group: Roll>] 
     185 
     186### Custom Tests ### 
     187 
     188# Let's see if we can query through our second relationship. 
     189>>> rock.custom_members.all() 
     190[] 
     191# We can query in the opposite direction as well. 
     192>>> bob.custom.all() 
     193[] 
     194 
     195# Let's create some membership objects in this custom relationship. 
     196>>> cm1 = CustomMembership.objects.create(person = bob, group = rock) 
     197>>> cm2 = CustomMembership.objects.create(person = jim, group = rock) 
     198 
     199# If we get the number of people in Rock, it should be both Bob and Jim. 
     200>>> rock.custom_members.all() 
     201[<Person: Bob>, <Person: Jim>] 
     202 
     203# Bob should only be in one custom group. 
     204>>> bob.custom.all() 
     205[<Group: Rock>] 
     206 
     207# Let's make sure our new descriptors don't conflict with the FK related_name. 
     208>>> bob.custom_person_related_name.all() 
     209[<CustomMembership: Bob is a member of Rock>] 
     210 
     211### QUERY TESTS ### 
     212 
     213# We can query for the related model by using its attribute name (members, in  
     214# this case). 
     215>>> Group.objects.filter(members__name='Bob') 
     216[<Group: Roll>] 
     217 
     218# To query through the intermediary model, we specify its model name. 
     219# In this case, membership. 
     220>>> Group.objects.filter(membership__invite_reason = "She was just awesome.") 
     221[<Group: Rock>] 
     222 
     223# If we want to query in the reverse direction by the related model, use its 
     224# model name (group, in this case). 
     225>>> Person.objects.filter(group__name="Rock") 
     226[<Person: Jim>, <Person: Jane>] 
     227 
     228# If the m2m field has specified a related_name, using that will work. 
     229>>> Person.objects.filter(custom__name="Rock") 
     230[<Person: Bob>, <Person: Jim>] 
     231 
     232# To query through the intermediary model in the reverse direction, we again 
     233# specify its model name (membership, in this case). 
     234>>> Person.objects.filter(membership__invite_reason = "She was just awesome.") 
     235[<Person: Jane>] 
     236 
     237# Let's see all of the groups that Jane joined after 1 Jan 2005: 
     238>>> Group.objects.filter(membership__date_joined__gt = datetime(2005, 1, 1),  
     239... membership__person = jane) 
     240[<Group: Rock>] 
     241 
     242# Queries also work in the reverse direction: Now let's see all of the people  
     243# that have joined Rock since 1 Jan 2005: 
     244>>> Person.objects.filter(membership__date_joined__gt = datetime(2005, 1, 1),  
     245... membership__group = rock) 
     246[<Person: Jim>, <Person: Jane>] 
     247 
     248# Conceivably, queries through membership could return correct, but non-unique 
     249# querysets.  To demonstrate this, we query for all people who have joined a  
     250# group after 2004: 
     251>>> Person.objects.filter(membership__date_joined__gt = datetime(2004, 1, 1)) 
     252[<Person: Jim>, <Person: Jim>, <Person: Jane>] 
     253 
     254# Jim showed up twice, because he joined two groups ('Rock', and 'Roll'): 
     255>>> [(m.person.name, m.group.name) for m in  
     256... Membership.objects.filter(date_joined__gt = datetime(2004, 1, 1))] 
     257[(u'Jim', u'Rock'), (u'Jane', u'Rock'), (u'Jim', u'Roll')] 
     258 
     259# QuerySet's distinct() method can correct this problem. 
     260>>> Person.objects.filter(membership__date_joined__gt = datetime(2004, 1, 1)).distinct() 
     261[<Person: Jim>, <Person: Jane>] 
     262"""}