1 """

     2 Various edge-cases for model managers.

     3 """

     4 

     5 from django.db import models

     6 

     7 class OnlyFred(models.Manager):

     8     def get_query_set(self):

     9         return super(OnlyFred, self).get_query_set().filter(name='fred')

    10 

    11 class OnlyBarney(models.Manager):

    12     def get_query_set(self):

    13         return super(OnlyBarney, self).get_query_set().filter(name='barney')

    14 

    15 class Value42(models.Manager):

    16     def get_query_set(self):

    17         return super(Value42, self).get_query_set().filter(value=42)

    18 

    19 class AbstractBase1(models.Model):

    20     name = models.CharField(max_length=50)

    21 

    22     class Meta:

    23         abstract = True

    24 

    25     # Custom managers

    26     manager1 = OnlyFred()

    27     manager2 = OnlyBarney()

    28     objects = models.Manager()

    29 

    30 class AbstractBase2(models.Model):

    31     value = models.IntegerField()

    32 

    33     class Meta:

    34         abstract = True

    35 

    36     # Custom manager

    37     restricted = Value42()

    38 

    39 # No custom manager on this class to make sure the default case doesn't break.

    40 class AbstractBase3(models.Model):

    41     comment = models.CharField(max_length=50)

    42 

    43     class Meta:

    44         abstract = True

    45 

    46 class Parent(models.Model):

    47     name = models.CharField(max_length=50)

    48 

    49     manager = OnlyFred()

    50 

    51     def __unicode__(self):

    52         return self.name

    53 

    54 # Managers from base classes are inherited and, if no manager is specified

    55 # *and* the parent has a manager specified, the first one (in the MRO) will

    56 # become the default.

    57 class Child1(AbstractBase1):

    58     data = models.CharField(max_length=25)

    59 

    60     def __unicode__(self):

    61         return self.data

    62 

    63 class Child2(AbstractBase1, AbstractBase2):

    64     data = models.CharField(max_length=25)

    65 

    66     def __unicode__(self):

    67         return self.data

    68 

    69 class Child3(AbstractBase1, AbstractBase3):

    70     data = models.CharField(max_length=25)

    71 

    72     def __unicode__(self):

    73         return self.data

    74 

    75 class Child4(AbstractBase1):

    76     data = models.CharField(max_length=25)

    77 

    78     # Should be the default manager, although the parent managers are

    79     # inherited.

    80     default = models.Manager()

    81 

    82     def __unicode__(self):

    83         return self.data

    84 

    85 class Child5(AbstractBase3):

    86     name = models.CharField(max_length=25)

    87 

    88     default = OnlyFred()

    89     objects = models.Manager()

    90 

    91     def __unicode__(self):

    92         return self.name

    93 

    94 # Will inherit managers from AbstractBase1, but not Child4.

    95 class Child6(Child4):

    96     value = models.IntegerField()

    97 

    98 # Will not inherit default manager from parent.

    99 class Child7(Parent):

   100     pass