Added ability to prefix database values. Fixes #24.

README.rst

@@ -128,6 +128,12 @@ the ``CACHES`` setting. E.g.::
     }
     CONSTANCE_DATABASE_CACHE_BACKEND = 'default'
 
+Just like the Redis backend you can set an optional prefix that is used during
+database interactions. To keep backward compatibility it defaults to ``''``
+(an empty string). To use something else do this::
+
+    CONSTANCE_DATABASE_PREFIX = 'constance:myproject:'
+
 .. _django-picklefield: http://pypi.python.org/pypi/django-picklefield/
 
 Usage

constance/backends/database/__init__.py

@@ -1,3 +1,5 @@
+import itertools
+
 from django.core.exceptions import ImproperlyConfigured
 from django.db.models.signals import post_save
 from django.core.cache import get_cache
@@ -16,6 +18,7 @@ if settings.DATABASE_CACHE_BACKEND:
             "it to a backend that supports cross-process caching."
             % settings.DATABASE_CACHE_BACKEND)
 
+
 class DatabaseBackend(Backend):
     def __init__(self):
         from constance.backends.database.models import Constance
@@ -27,11 +30,19 @@ class DatabaseBackend(Backend):
         # Clear simple cache.
         post_save.connect(self.clear, sender=self._model)
 
+    def add_prefix(self, key):
+        return "%s%s" % (self._prefix, key)
+
     def mget(self, keys):
-        for const in self._model._default_manager.filter(key__in=keys):
-            yield const.key, const.value
+        if not keys:
+            return
+        prefixed_keys = [self.add_prefix(key) for key in keys]
+        stored = self._model._default_manager.filter(key__in=prefixed_keys)
+        for key, const in itertools.izip(keys, stored):
+            yield key, const.value
 
     def get(self, key):
+        key = self.add_prefix(key)
         value = None
         if db_cache:
             value = db_cache.get(key)
@@ -47,7 +58,7 @@ class DatabaseBackend(Backend):
 
     def set(self, key, value):
         constance, created = self._model._default_manager.get_or_create(
-            key=key, defaults={'value': value}
+            key=self.add_prefix(key), defaults={'value': value}
         )
         if not created:
             constance.value = value

constance/backends/database/models.py

@@ -10,6 +10,7 @@ except ImportError:
                                "django-picklefield which is required for "
                                "the constance database backend.")
 
+
 class Constance(models.Model):
     key = models.CharField(max_length=255, unique=True)
     value = PickledObjectField()

constance/backends/redisd.py

@@ -15,7 +15,7 @@ class RedisBackend(Backend):
 
     def __init__(self):
         super(RedisBackend, self).__init__()
-        self._prefix = settings.PREFIX
+        self._prefix = settings.REDIS_PREFIX
         connection_cls = settings.CONNECTION_CLASS
         if connection_cls is not None:
             self._rd = utils.import_module_attr(connection_cls)()

constance/settings.py

@@ -21,4 +21,6 @@ REDIS_CONNECTION = getattr(settings, 'CONSTANCE_REDIS_CONNECTION',
 DATABASE_CACHE_BACKEND = getattr(settings, 'CONSTANCE_DATABASE_CACHE_BACKEND',
                                  None)
 
+DATABASE_PREFIX = getattr(settings, 'CONSTANCE_DATABASE_PREFIX', '')
+
 SUPERUSER_ONLY = getattr(settings, 'CONSTANCE_SUPERUSER_ONLY', True)