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[multi-db] Added install() and other schema manipulation methods to Manager. Fixed bug in manager assignment for inherited classes (objects and _default_manager in child class were still those belonging to parent class).
git-svn-id: http://code.djangoproject.com/svn/django/branches/multiple-db-support@3266 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Jason Pellerin
parent
54d611d2a2
commit
f194f74aa6
@ -20,7 +20,9 @@ def ensure_default_manager(sender):
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except FieldDoesNotExist:
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pass
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cls.add_to_class('objects', Manager())
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elif cls._default_manager.model != cls:
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# cls is an inherited model; don't want the parent manager
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cls.add_to_class('objects', Manager())
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dispatcher.connect(ensure_default_manager, signal=signals.class_prepared)
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class Manager(object):
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@ -38,7 +40,9 @@ class Manager(object):
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# TODO: Use weakref because of possible memory leak / circular reference.
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self.model = model
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setattr(model, name, ManagerDescriptor(self))
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if not hasattr(model, '_default_manager') or self.creation_counter < model._default_manager.creation_counter:
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if not hasattr(model, '_default_manager') \
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or self.creation_counter < model._default_manager.creation_counter \
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or model._default_manager.model != model:
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model._default_manager = self
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#######################
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@ -102,6 +106,38 @@ class Manager(object):
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def values(self, *args, **kwargs):
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return self.get_query_set().values(*args, **kwargs)
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#######################
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# SCHEMA MANIPULATION #
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#######################
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def install(self, initial_data=False):
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"""Install my model's table, indexes and (if requested) initial data.
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Returns a 2-tuple of the lists of statements executed and
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statements pending. Pending statements are those that could
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not yet be executed, such as foreign key constraints for
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tables that don't exist at install time.
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"""
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creator = self.model._meta.connection_info.get_creation_module()
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run, pending = creator.builder.get_create_table(self.model)
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run += creator.builder.get_create_indexes(self.model)
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pending += creator.builder.get_create_many_to_many(self.model)
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if initial_data:
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run += creator.builder.get_initialdata(self.model)
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for statement in run:
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statement.execute()
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return pending
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def load_initial_data(self):
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"""Load initial data for my model into the database."""
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pass # FIXME
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def drop(self):
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"""Drop my model's table."""
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pass # FIXME
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class ManagerDescriptor(object):
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# This class ensures managers aren't accessible via model instances.
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# For example, Poll.objects works, but poll_obj.objects raises AttributeError.
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131
tests/othertests/manager_schema_manipulation.py
Normal file
131
tests/othertests/manager_schema_manipulation.py
Normal file
@ -0,0 +1,131 @@
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"""
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# Django uses a model's default manager to perform schema manipulations such as
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# creating or dropping the model's table.
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>>> from django.db import models
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# default connection
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>>> class DA(models.Model):
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... name = models.CharField(maxlength=20)
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...
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... def __str__(self):
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... return self.name
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# connection django_test_db_a
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>>> class PA(models.Model):
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... name = models.CharField(maxlength=20)
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... # This creates a cycle in the dependency graph
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... c = models.ForeignKey('PC', null=True)
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...
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... def __str__(self):
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... return self.name
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...
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... class Meta:
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... db_connection = 'django_test_db_a'
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>>> class PB(models.Model):
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... name = models.CharField(maxlength=20)
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... a = models.ForeignKey(PA)
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...
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... def __str__(self):
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... return self.name
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...
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... class Meta:
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... db_connection = 'django_test_db_a'
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>>> class PC(models.Model):
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... name = models.CharField(maxlength=20)
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... b = models.ForeignKey(PB)
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...
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... def __str__(self):
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... return self.name
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...
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... class Meta:
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... db_connection = 'django_test_db_a'
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# connection django_test_db_b
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>>> class QA(models.Model):
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... name = models.CharField(maxlength=20)
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...
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... def __str__(self):
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... return self.name
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...
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... class Meta:
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... db_connection = 'django_test_db_b'
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>>> class QB(models.Model):
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... name = models.CharField(maxlength=20)
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... a = models.ForeignKey(QA)
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...
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... def __str__(self):
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... return self.name
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...
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... class Meta:
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... db_connection = 'django_test_db_b'
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# many-many
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>>> class QC(models.Model):
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... name = models.CharField(maxlength=20)
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...
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... def __str__(self):
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... return self.name
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...
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... class Meta:
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... db_connection = 'django_test_db_b'
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>>> class QD(models.Model):
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... name = models.CharField(maxlength=20)
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... qcs = models.ManyToManyField(QC)
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...
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... def __str__(self):
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... return self.name
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...
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... class Meta:
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... db_connection = 'django_test_db_b'
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# Using the manager, models can be installed individually, whether they
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# use the default connection or a named connection.
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>>> DA.objects.install()
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[]
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>>> QA.objects.install()
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[]
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>>> QB.objects.install()
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[]
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>>> DA.objects.all()
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[]
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>>> list(QA.objects.all())
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[]
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>>> list(QB.objects.all())
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[]
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>>> QA(name="something").save()
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>>> QA.objects.all()
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[<QA: something>]
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# The `install()` method returns a tuple, the first element of which is a
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# list of statements that were executed, and the second, pending
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# statements that could not be executed because (for instance) they are
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# meant to establish foreign key relationships to tables that don't
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# exist. These are bound to the model's connection and should
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# be executed after all models in the app have been installed.
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# NOTE: pretend db supports constraints for this test
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>>> real_cnst = PA._meta.connection_info.backend.supports_constraints
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>>> PA._meta.connection_info.backend.supports_constraints = True
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>>> result = PA.objects.install()
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>>> result
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[BoundStatement('ALTER TABLE "othertests_pa" ADD CONSTRAINT "c_id_referencing_othertests_pc_id" FOREIGN KEY ("c_id") REFERENCES "othertests_pc" ("id");')]
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# NOTE: restore real constraint flag
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>>> PA._meta.connection_info.backend.supports_constraints = real_cnst
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# Models with many-many relationships will also have pending statement
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# lists. Like other pending statements, these should be executed after
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# all models in the app have been installed.
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>>> QC.objects.install()
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[]
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>>> QD.objects.install()
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[BoundStatement('CREATE TABLE "othertests_qd_qcs" (...);')]
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"""
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