diff --git a/django/db/backends/oracle/base.py b/django/db/backends/oracle/base.py
index efec3e58f1..c5da7ac25c 100644
--- a/django/db/backends/oracle/base.py
+++ b/django/db/backends/oracle/base.py
@@ -466,10 +466,11 @@ def get_query_set_class(DefaultQuerySet):
             for value, field in map(None, row, fields):
                 if isinstance(value, Database.LOB):
                     value = value.read()
-                # Since Oracle won't distinguish between NULL and an empty
-                # string (''), we store empty strings as a space.  Here is
-                # where we undo that treachery.
-                if value == ' ':
+                # Oracle stores empty strings as null. We need to undo this in
+                # order to adhere to the Django convention of using the empty
+                # string instead of null, but only if the field accepts the
+                # empty string.
+                if value is None and field.empty_strings_allowed:
                     value = ''
                 # Convert 1 or 0 to True or False
                 elif value in (1, 0) and isinstance(field, (BooleanField, NullBooleanField)):
diff --git a/django/db/models/fields/__init__.py b/django/db/models/fields/__init__.py
index f9aed8b98e..0afd8471fd 100644
--- a/django/db/models/fields/__init__.py
+++ b/django/db/models/fields/__init__.py
@@ -76,6 +76,10 @@ class Field(object):
         self.primary_key = primary_key
         self.maxlength, self.unique = maxlength, unique
         self.blank, self.null = blank, null
+        # Oracle treats the empty string ('') as null, so coerce the null
+        # option whenever '' is a possible value.
+        if self.empty_strings_allowed and settings.DATABASE_ENGINE == 'oracle':
+            self.null = True
         self.core, self.rel, self.default = core, rel, default
         self.editable = editable
         self.serialize = serialize
@@ -162,10 +166,6 @@ class Field(object):
 
     def get_db_prep_save(self, value):
         "Returns field's value prepared for saving into a database."
-        # Oracle treats empty strings ('') the same as NULLs.
-        # To get around this wart, we need to change it to something else...
-        if settings.DATABASE_ENGINE == 'oracle' and value == '':
-            value = ' '
         return value
 
     def get_db_prep_lookup(self, lookup_type, value):