Added a new description_encoding attribute on the dialect.

This is used for encoding the column name when processing the metadata. This
usually defaults to utf-8.

2 files changed, 13 insertions, 3 deletions

diff --git a/lib/sqlalchemy/engine/base.py b/lib/sqlalchemy/engine/base.py
index 24fd1cc6e..c547c0e54 100644
--- a/lib/sqlalchemy/engine/base.py
+++ b/lib/sqlalchemy/engine/base.py
@@ -107,6 +107,11 @@ class Dialect(object):
 
     supports_default_values
       Indicates if the construct ``INSERT INTO tablename DEFAULT VALUES`` is supported
+
+    description_encoding
+      type of encoding to use for unicode when working with metadata
+      descriptions. If set to ``None`` no encoding will be done.
+      This usually defaults to 'utf-8'.
     """
 
     def create_connect_args(self, url):
@@ -1441,7 +1446,9 @@ class ResultProxy(object):
         typemap = self.dialect.dbapi_type_map
 
         for i, item in enumerate(metadata):
-            colname = item[0].decode(self.dialect.encoding)
+            colname = item[0]
+            if self.dialect.description_encoding:
+                colname = colname.decode(self.dialect.description_encoding)
 
             if '.' in colname:
                 # sqlite will in some circumstances prepend table name to colnames, so strip
diff --git a/lib/sqlalchemy/engine/default.py b/lib/sqlalchemy/engine/default.py
index 682ab526c..8a44bac74 100644
--- a/lib/sqlalchemy/engine/default.py
+++ b/lib/sqlalchemy/engine/default.py
@@ -40,7 +40,9 @@ class DefaultDialect(base.Dialect):
     supports_default_values = False 
     supports_empty_insert = True
 
-    def __init__(self, convert_unicode=False, assert_unicode=False, encoding='utf-8', paramstyle=None, dbapi=None, label_length=None, **kwargs):
+    def __init__(self, convert_unicode=False, assert_unicode=False,
+                 encoding='utf-8', paramstyle=None, dbapi=None, 
+                 label_length=None, description_encoding='utf-8', **kwargs):
         self.convert_unicode = convert_unicode
         self.assert_unicode = assert_unicode
         self.encoding = encoding
@@ -58,6 +60,7 @@ class DefaultDialect(base.Dialect):
         if label_length and label_length > self.max_identifier_length:
             raise exc.ArgumentError("Label length of %d is greater than this dialect's maximum identifier length of %d" % (label_length, self.max_identifier_length))
         self.label_length = label_length
+        self.description_encoding = description_encoding
 
     def type_descriptor(self, typeobj):
         """Provide a database-specific ``TypeEngine`` object, given
@@ -368,4 +371,4 @@ class DefaultExecutionContext(base.ExecutionContext):
             self.postfetch_cols = self.compiled.postfetch
             self.prefetch_cols = self.compiled.prefetch
 
-DefaultDialect.execution_ctx_cls = DefaultExecutionContext
\ No newline at end of file
+DefaultDialect.execution_ctx_cls = DefaultExecutionContext