Fix dbapi error attribute

Author: Simon-Chenzw

clickhouse_sqlalchemy/drivers/asynch/connector.py

@@ -114,10 +114,8 @@ def __init__(self, asynch):
         self.paramstyle = 'pyformat'
         self._init_dbapi_attributes()
 
-    class Error(Exception):
-        pass
-
     def _init_dbapi_attributes(self):
+        self.Error = self.asynch.errors.ClickHouseException
         for name in (
                 'ServerException',
                 'UnexpectedPacketFromServerError',

clickhouse_sqlalchemy/drivers/http/connector.py

@@ -9,14 +9,7 @@
 threadsafety = 2
 # Python extended format codes, e.g. ...WHERE name=%(name)s
 paramstyle = 'pyformat'
-
-
-class Error(Exception):
-    """
-    Exception that is the base class of all other error exceptions.
-    You can use this to catch all errors with one single except statement.
-    """
-    pass
+Error = Exception
 
 
 def connect(*args, **kwargs):

clickhouse_sqlalchemy/drivers/native/connector.py

@@ -11,14 +11,7 @@
 threadsafety = 2
 # Python extended format codes, e.g. ...WHERE name=%(name)s
 paramstyle = 'pyformat'
-
-
-class Error(Exception):
-    """
-    Exception that is the base class of all other error exceptions.
-    You can use this to catch all errors with one single except statement.
-    """
-    pass
+Error = DatabaseException
 
 
 def connect(*args, **kwargs):