- Added func.min(), func.max(), func.sum() as "generic functions",

which basically allows for their return type to be determined
automatically.  Helps with dates on SQLite, decimal types,
others. [ticket:1160]

- added decimal.Decimal as an "auto-detect" type; bind parameters
and generic functions will set their type to Numeric when a
Decimal is used.

2 files changed, 16 insertions, 2 deletions

diff --git a/lib/sqlalchemy/sql/functions.py b/lib/sqlalchemy/sql/functions.py
index 7fce3b95b..c7a0f142d 100644
--- a/lib/sqlalchemy/sql/functions.py
+++ b/lib/sqlalchemy/sql/functions.py
@@ -36,12 +36,25 @@ class AnsiFunction(GenericFunction):
     def __init__(self, **kwargs):
         GenericFunction.__init__(self, **kwargs)
 
-
-class coalesce(GenericFunction):
+class ReturnTypeFromArgs(GenericFunction):
+    """Define a function whose return type is the same as its arguments."""
+    
     def __init__(self, *args, **kwargs):
         kwargs.setdefault('type_', _type_from_args(args))
         GenericFunction.__init__(self, args=args, **kwargs)
 
+class coalesce(ReturnTypeFromArgs):
+    pass
+
+class max(ReturnTypeFromArgs):
+    pass
+
+class min(ReturnTypeFromArgs):
+    pass
+
+class sum(ReturnTypeFromArgs):
+    pass
+
 class now(GenericFunction):
     __return_type__ = sqltypes.DateTime
 
diff --git a/lib/sqlalchemy/types.py b/lib/sqlalchemy/types.py
index 3690ed3ca..4958e4812 100644
--- a/lib/sqlalchemy/types.py
+++ b/lib/sqlalchemy/types.py
@@ -625,6 +625,7 @@ type_map = {
     unicode : NCHAR,
     int : Integer,
     float : Numeric,
+    _python_Decimal : Numeric,
     dt.date : Date,
     dt.datetime : DateTime,
     dt.time : Time,