Fixed #3163 -- Add a "Meta.managed" option to models.

This allows a model to be defined which is not subject to database table
creation and removal. Useful for models that sit over existing tables or
database views.

Thanks to Alexander Myodov, Wolfgang Kriesing and Ryan Kelly for the bulk of
this patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@10008 bcc190cf-cafb-0310-a4f2-bffc1f526a37

3 files changed, 16 insertions, 1 deletions

diff --git a/django/db/backends/__init__.py b/django/db/backends/__init__.py
index 6b027de193..5a3cb53842 100644
--- a/django/db/backends/__init__.py
+++ b/django/db/backends/__init__.py
@@ -450,6 +450,8 @@ class BaseDatabaseIntrospection(object):
         tables = set()
         for app in models.get_apps():
             for model in models.get_models(app):
+                if not model._meta.managed:
+                    continue
                 tables.add(model._meta.db_table)
                 tables.update([f.m2m_db_table() for f in model._meta.local_many_to_many])
         if only_existing:
@@ -476,6 +478,8 @@ class BaseDatabaseIntrospection(object):
 
         for app in apps:
             for model in models.get_models(app):
+                if not model._meta.managed:
+                    continue
                 for f in model._meta.local_fields:
                     if isinstance(f, models.AutoField):
                         sequence_list.append({'table': model._meta.db_table, 'column': f.column})
diff --git a/django/db/backends/creation.py b/django/db/backends/creation.py
index e6399874ef..9bebce9065 100644
--- a/django/db/backends/creation.py
+++ b/django/db/backends/creation.py
@@ -33,6 +33,8 @@ class BaseDatabaseCreation(object):
         from django.db import models
 
         opts = model._meta
+        if not opts.managed:
+            return [], {}
         final_output = []
         table_output = []
         pending_references = {}
@@ -112,6 +114,8 @@ class BaseDatabaseCreation(object):
         "Returns any ALTER TABLE statements to add constraints after the fact."
         from django.db.backends.util import truncate_name
 
+        if not model._meta.managed:
+            return []
         qn = self.connection.ops.quote_name
         final_output = []
         opts = model._meta
@@ -225,6 +229,8 @@ class BaseDatabaseCreation(object):
 
     def sql_indexes_for_model(self, model, style):
         "Returns the CREATE INDEX SQL statements for a single model"
+        if not model._meta.managed:
+            return []
         output = []
         for f in model._meta.local_fields:
             output.extend(self.sql_indexes_for_field(model, f, style))
@@ -255,6 +261,8 @@ class BaseDatabaseCreation(object):
 
     def sql_destroy_model(self, model, references_to_delete, style):
         "Return the DROP TABLE and restraint dropping statements for a single model"
+        if not model._meta.managed:
+            return []
         # Drop the table now
         qn = self.connection.ops.quote_name
         output = ['%s %s;' % (style.SQL_KEYWORD('DROP TABLE'),
@@ -271,6 +279,8 @@ class BaseDatabaseCreation(object):
     def sql_remove_table_constraints(self, model, references_to_delete, style):
         from django.db.backends.util import truncate_name
 
+        if not model._meta.managed:
+            return []
         output = []
         qn = self.connection.ops.quote_name
         for rel_class, f in references_to_delete[model]:
diff --git a/django/db/models/options.py b/django/db/models/options.py
index 06e17c61ad..2dd3d256a1 100644
--- a/django/db/models/options.py
+++ b/django/db/models/options.py
@@ -21,7 +21,7 @@ get_verbose_name = lambda class_name: re.sub('(((?<=[a-z])[A-Z])|([A-Z](?![A-Z]|
 DEFAULT_NAMES = ('verbose_name', 'db_table', 'ordering',
                  'unique_together', 'permissions', 'get_latest_by',
                  'order_with_respect_to', 'app_label', 'db_tablespace',
-                 'abstract')
+                 'abstract', 'managed')
 
 class Options(object):
     def __init__(self, meta, app_label=None):
@@ -42,6 +42,7 @@ class Options(object):
         self.pk = None
         self.has_auto_field, self.auto_field = False, None
         self.abstract = False
+        self.managed = True
         self.parents = SortedDict()
         self.duplicate_targets = {}
         # Managers that have been inherited from abstract base classes. These