fixes to types so that database-specific types more easily used;

fixes to mysql text types to work with this methodology
[ticket:269]

2 files changed, 12 insertions, 13 deletions

diff --git a/lib/sqlalchemy/databases/mysql.py b/lib/sqlalchemy/databases/mysql.py
index 56f2125ac..14e26438f 100644
--- a/lib/sqlalchemy/databases/mysql.py
+++ b/lib/sqlalchemy/databases/mysql.py
@@ -115,28 +115,19 @@ class MSText(sqltypes.TEXT):
         super(MSText, self).__init__()
     def get_col_spec(self):
         return "TEXT"
-class MSTinyText(sqltypes.TEXT):
-    def __init__(self, **kw):
-        self.binary = 'binary' in kw
-        super(MSTinyText, self).__init__()
+class MSTinyText(MSText):
     def get_col_spec(self):
         if self.binary:
             return "TEXT BINARY"
         else:
            return "TEXT"
-class MSMediumText(sqltypes.TEXT):
-    def __init__(self, **kw):
-        self.binary = 'binary' in kw
-        super(MSMediumText, self).__init__()
+class MSMediumText(MSText):
     def get_col_spec(self):
         if self.binary:
             return "MEDIUMTEXT BINARY"
         else:
             return "MEDIUMTEXT"
-class MSLongText(sqltypes.TEXT):
-    def __init__(self, **kw):
-        self.binary = 'binary' in kw
-        super(MSLongText, self).__init__()
+class MSLongText(MSText):
     def get_col_spec(self):
         if self.binary:
             return "LONGTEXT BINARY"
@@ -431,6 +422,7 @@ class MySQLCompiler(ansisql.ANSICompiler):
         
 class MySQLSchemaGenerator(ansisql.ANSISchemaGenerator):
     def get_column_specification(self, column, override_pk=False, first_pk=False):
+        t = column.type.engine_impl(self.engine)
         colspec = self.preparer.format_column(column) + " " + column.type.engine_impl(self.engine).get_col_spec()
         default = self.get_column_default_string(column)
         if default is not None:
diff --git a/lib/sqlalchemy/types.py b/lib/sqlalchemy/types.py
index 5fc75678d..709c77e5c 100644
--- a/lib/sqlalchemy/types.py
+++ b/lib/sqlalchemy/types.py
@@ -37,7 +37,7 @@ class TypeEngine(AbstractType):
     def dialect_impl(self, dialect):
         try:
             return self.impl_dict[dialect]
-        except:
+        except KeyError:
             return self.impl_dict.setdefault(dialect, dialect.type_descriptor(self))
     def _get_impl(self):
         if hasattr(self, '_impl'):
@@ -96,6 +96,7 @@ def to_instance(typeobj):
 def adapt_type(typeobj, colspecs):
     if isinstance(typeobj, type):
         typeobj = typeobj()
+    
     for t in typeobj.__class__.__mro__[0:-1]:
         try:
             impltype = colspecs[t]
@@ -105,6 +106,12 @@ def adapt_type(typeobj, colspecs):
     else:
         # couldnt adapt...raise exception ?
         return typeobj
+    # if we adapted the given generic type to a database-specific type, 
+    # but it turns out the originally given "generic" type
+    # is actually a subclass of our resulting type, then we were already
+    # were given a more specific type than that required; so use that.
+    if (issubclass(typeobj.__class__, impltype)):
+        return typeobj
     return typeobj.adapt(impltype)
     
 class NullTypeEngine(TypeEngine):