Fix bug #136

sqlalchemy_exasol/pyodbc.py

@@ -175,28 +175,13 @@ def _is_sql_fallback_requested(**kwargs):
             logger.warning("Using sql fallback instead of odbc functions")
         return is_fallback_requested
 
-    def _get_odbc_connection(self, connection):
-        if isinstance(connection, Engine):
-            odbc_connection = connection.raw_connection().connection
-        elif isinstance(connection, Session):
-            odbc_connection = connection.connection()
-            return self._get_odbc_connection(odbc_connection)
-        elif isinstance(connection, Connection):
-            odbc_connection = connection.connection.connection
-        else:
-            return None
-        if "pyodbc.Connection" in str(type(odbc_connection)):
-            return odbc_connection
-        else:
-            return None
-
     @reflection.cache
-    def _get_tables_for_schema_odbc(self, connection, odbc_connection, schema, table_type=None, table_name=None, **kw):
+    def _get_tables_for_schema_odbc(self, connection, schema, table_type=None, table_name=None, **kw):
         schema = self._get_schema_for_input_or_current(connection, schema)
         table_name = self.denormalize_name(table_name)
-        with odbc_connection.cursor().tables(schema=schema, tableType=table_type, table=table_name) as table_cursor:
-            rows = [row for row in table_cursor]
-            return rows
+        conn = connection.engine.raw_connection()
+        with conn.cursor().tables(schema=schema, tableType=table_type, table=table_name) as table_cursor:
+            return [row for row in table_cursor]
 
     @reflection.cache
     def get_view_definition(self, connection, view_name, schema=None, **kw):
@@ -205,9 +190,8 @@ def get_view_definition(self, connection, view_name, schema=None, **kw):
         if view_name is None:
             return None
 
-        odbc_connection = self._get_odbc_connection(connection)
         tables = self._get_tables_for_schema_odbc(
-            connection, odbc_connection, schema,
+            connection, schema,
             table_type="VIEW",
             table_name=view_name,
             **kw
@@ -229,10 +213,9 @@ def get_view_definition(self, connection, view_name, schema=None, **kw):
     def get_table_names(self, connection, schema, **kw):
         if self._is_sql_fallback_requested(**kw):
             return super().get_table_names(connection, schema, **kw)
-        odbc_connection = self._get_odbc_connection(connection)
         tables = self._get_tables_for_schema_odbc(
             connection,
-            odbc_connection,
+
             schema, table_type="TABLE",
             **kw
         )
@@ -242,10 +225,8 @@ def get_table_names(self, connection, schema, **kw):
     def get_view_names(self, connection, schema=None, **kw):
         if self._is_sql_fallback_requested(**kw):
             return super().get_view_names(connection, schema, **kw)
-        odbc_connection = self._get_odbc_connection(connection)
         tables = self._get_tables_for_schema_odbc(
             connection,
-            odbc_connection,
             schema,
             table_type="VIEW",
             **kw
@@ -273,9 +254,8 @@ def _get_columns(self, connection, table_name, schema=None, **kw):
         if self._is_sql_fallback_requested(**kw):
             return super()._get_columns(connection, table_name, schema, **kw)
 
-        odbc_connection = self._get_odbc_connection(connection)
         tables = self._get_tables_for_schema_odbc(
-            connection, odbc_connection,
+            connection,
             schema=schema,
             table_name=table_name,
             **kw
@@ -301,10 +281,10 @@ def _get_pk_constraint(self, connection, table_name, schema=None, **kw):
         if self._is_sql_fallback_requested(**kw):
             return super()._get_pk_constraint(connection, table_name, schema, **kw)
 
-        odbc_connection = self._get_odbc_connection(connection)
+        conn = connection.engine.raw_connection()
         schema = self._get_schema_for_input_or_current(connection, schema)
         table_name = self.denormalize_name(table_name)
-        with odbc_connection.cursor().primaryKeys(table=table_name, schema=schema) as cursor:
+        with conn.cursor().primaryKeys(table=table_name, schema=schema) as cursor:
             pkeys = []
             constraint_name = None
             for row in cursor:
@@ -320,11 +300,9 @@ def _get_foreign_keys(self, connection, table_name, schema=None, **kw):
         if self._is_sql_fallback_requested(**kw):
             return super()._get_foreign_keys(connection, table_name, schema, **kw)
 
-        odbc_connection = self._get_odbc_connection(connection)
         # Need to use a workaround, because SQLForeignKeys functions doesn't work for an unknown reason
         tables = self._get_tables_for_schema_odbc(
             connection=connection,
-            odbc_connection=odbc_connection,
             schema=schema,
             table_name=table_name,
             table_type="TABLE",