Corrected handling of large decimal values on mssql. Added more robust tests.

- Removed string manipulation on floats. Float types are now passed through
  to mssql as is.
- Fixes #1280

1 files changed, 10 insertions, 25 deletions

diff --git a/lib/sqlalchemy/databases/mssql.py b/lib/sqlalchemy/databases/mssql.py
index 7d23c5b27..24296c329 100644
--- a/lib/sqlalchemy/databases/mssql.py
+++ b/lib/sqlalchemy/databases/mssql.py
@@ -332,16 +332,17 @@ class MSNumeric(sqltypes.Numeric):
                 # Not sure that this exception is needed
                 return value
             else:
-                # FIXME: this will not correct a situation where a float
-                # gets converted to e-notation.
-                if isinstance(value, decimal.Decimal) and value._exp < -6:
-                    value = ((value < 0 and '-' or '')
-                        + '0.'
-                        + '0' * -(value._exp+1)
-                        + value._int)
-                    return value
+                if isinstance(value, decimal.Decimal):
+                    sign = (value < 0 and '-' or '') 
+                    if value._exp > -1:
+                        return float(sign + value._int + '0' * value._exp)
+                    else:
+                        s = value._int.zfill(-value._exp+1)
+                        pos = len(s) + value._exp
+                        return sign + s[:pos] + '.' + s[pos:]
                 else:
-                    return str(value)
+                    return value
+
         return process
 
     def get_col_spec(self):
@@ -358,14 +359,6 @@ class MSFloat(sqltypes.Float):
         else:
             return "FLOAT(%(precision)s)" % {'precision': self.precision}
 
-    def bind_processor(self, dialect):
-        def process(value):
-            """By converting to string, we can use Decimal types round-trip."""
-            if not value is None:
-                return str(value)
-            return None
-        return process
-
 
 class MSReal(MSFloat):
     """A type for ``real`` numbers."""
@@ -380,14 +373,6 @@ class MSReal(MSFloat):
     def adapt(self, impltype):
         return impltype()
 
-    def bind_processor(self, dialect):
-        def process(value):
-            if value is not None:
-                return float(value)
-            else:
-                return value
-        return process
-
     def get_col_spec(self):
         return "REAL"