re-introduce get_schema_desc

Signed-off-by: varun-edachali-dbx <varun.edachali@databricks.com>

Author: varun-edachali-dbx

src/databricks/sql/backend/types.py

@@ -299,7 +299,6 @@ def __init__(
         self.guid = guid
         self.secret = secret
 
-    
     def __str__(self) -> str:
         """
         Return a string representation of the CommandId.

src/databricks/sql/result_set.py

@@ -59,12 +59,12 @@ def __init__(
             has_been_closed_server_side: Whether the command has been closed on the server
             has_more_rows: Whether the command has more rows
             results_queue: The results queue
-            description: column description of the results 
+            description: column description of the results
             is_staging_operation: Whether the command is a staging operation
         """
 
         self.connection = connection
-        self.backend = backend  
+        self.backend = backend
         self.arraysize = arraysize
         self.buffer_size_bytes = buffer_size_bytes
         self._next_row_index = 0
@@ -400,6 +400,23 @@ def fetchmany(self, size: int) -> List[Row]:
         else:
             return self._convert_arrow_table(self.fetchmany_arrow(size))
 
+    @staticmethod
+    def _get_schema_description(table_schema_message):
+        """
+        Takes a TableSchema message and returns a description 7-tuple as specified by PEP-249
+        """
+
+        def map_col_type(type_):
+            if type_.startswith("decimal"):
+                return "decimal"
+            else:
+                return type_
+
+        return [
+            (column.name, map_col_type(column.datatype), None, None, None, None, None)
+            for column in table_schema_message.columns
+        ]
+
 
 class SeaResultSet(ResultSet):
     """ResultSet implementation for SEA backend."""