3 files changed, 21 insertions, 30 deletions
diff --git a/lib/sqlalchemy/databases/maxdb.py b/lib/sqlalchemy/databases/maxdb.py
index 09cc9f0b6..3ca1bd61c 100644
--- a/lib/sqlalchemy/databases/maxdb.py
+++ b/lib/sqlalchemy/databases/maxdb.py
@@ -480,6 +480,21 @@ class MaxDBDialect(default.DefaultDialect):
         super(MaxDBDialect, self).__init__(**kw)
         self._raise_known = _raise_known_sql_errors
 
+        if self.dbapi is None:
+            self.dbapi_type_map = {}
+        else:
+            self.dbapi_type_map = {
+                'Long Binary': MaxBlob(),
+                'Long byte_t': MaxBlob(),
+                'Long Unicode': MaxText(),
+                'Timestamp': MaxTimestamp(),
+                'Date': MaxDate(),
+                'Time': MaxTime(),
+                datetime.datetime: MaxTimestamp(),
+                datetime.date: MaxDate(),
+                datetime.time: MaxTime(),
+            }
+
     def dbapi(cls):
         from sapdb import dbapi as _dbapi
         return _dbapi
@@ -498,22 +513,6 @@ class MaxDBDialect(default.DefaultDialect):
         else:
             return sqltypes.adapt_type(typeobj, colspecs)
 
-    def dbapi_type_map(self):
-        if self.dbapi is None:
-            return {}
-        else:
-            return {
-                'Long Binary': MaxBlob(),
-                'Long byte_t': MaxBlob(),
-                'Long Unicode': MaxText(),
-                'Timestamp': MaxTimestamp(),
-                'Date': MaxDate(),
-                'Time': MaxTime(),
-                datetime.datetime: MaxTimestamp(),
-                datetime.date: MaxDate(),
-                datetime.time: MaxTime(),
-            }
-
     def create_execution_context(self, connection, **kw):
         return MaxDBExecutionContext(self, connection, **kw)
 
diff --git a/lib/sqlalchemy/databases/oracle.py b/lib/sqlalchemy/databases/oracle.py
index 71c82bfd8..9c9c54bf6 100644
--- a/lib/sqlalchemy/databases/oracle.py
+++ b/lib/sqlalchemy/databases/oracle.py
@@ -251,24 +251,19 @@ class OracleDialect(default.DefaultDialect):
         self.supports_timestamp = self.dbapi is None or hasattr(self.dbapi, 'TIMESTAMP' )
         self.auto_setinputsizes = auto_setinputsizes
         self.auto_convert_lobs = auto_convert_lobs
-        
-        if self.dbapi is not None:
-            self.ORACLE_BINARY_TYPES = [getattr(self.dbapi, k) for k in ["BFILE", "CLOB", "NCLOB", "BLOB"] if hasattr(self.dbapi, k)]
-        else:
+        if self.dbapi is None or not self.auto_convert_lobs or not 'CLOB' in self.dbapi.__dict__:
+            self.dbapi_type_map = {}
             self.ORACLE_BINARY_TYPES = []
-
-    def dbapi_type_map(self):
-        if self.dbapi is None or not self.auto_convert_lobs:
-            return {}
         else:
             # only use this for LOB objects.  using it for strings, dates
             # etc. leads to a little too much magic, reflection doesn't know if it should
             # expect encoded strings or unicodes, etc.
-            return {
+            self.dbapi_type_map = {
                 self.dbapi.CLOB: OracleText(), 
                 self.dbapi.BLOB: OracleBinary(), 
                 self.dbapi.BINARY: OracleRaw(), 
             }
+            self.ORACLE_BINARY_TYPES = [getattr(self.dbapi, k) for k in ["BFILE", "CLOB", "NCLOB", "BLOB"] if hasattr(self.dbapi, k)]
 
     def dbapi(cls):
         import cx_Oracle
diff --git a/lib/sqlalchemy/databases/sybase.py b/lib/sqlalchemy/databases/sybase.py
index 022f54746..87045d192 100644
--- a/lib/sqlalchemy/databases/sybase.py
+++ b/lib/sqlalchemy/databases/sybase.py
@@ -639,8 +639,7 @@ class SybaseSQLDialect_mxodbc(SybaseSQLDialect):
     def __init__(self, **params):
         super(SybaseSQLDialect_mxodbc, self).__init__(**params)
 
-    def dbapi_type_map(self):
-        return {'getdate' : SybaseDate_mxodbc()}
+        self.dbapi_type_map = {'getdate' : SybaseDate_mxodbc()}
         
     def import_dbapi(cls):
         #import mx.ODBC.Windows as module
@@ -686,9 +685,7 @@ class SybaseSQLDialect_mxodbc(SybaseSQLDialect):
 class SybaseSQLDialect_pyodbc(SybaseSQLDialect):
     def __init__(self, **params):
         super(SybaseSQLDialect_pyodbc, self).__init__(**params)
-
-    def dbapi_type_map(self):
-        return {'getdate' : SybaseDate_pyodbc()}
+        self.dbapi_type_map = {'getdate' : SybaseDate_pyodbc()}
 
     def import_dbapi(cls):
         import mypyodbc as module