Switch column introspection to use sp_columns instead of cursor.columns

Author: wgordon17

sql_server/pyodbc/introspection.py

@@ -93,8 +93,9 @@ def get_table_description(self, cursor, table_name, identity_check=True):
         of SQL_BIGAUTOFIELD, which maps to the 'BigAutoField' value in the DATA_TYPES_REVERSE dict.
         """
 
-        # map pyodbc's cursor.columns to db-api cursor description
-        columns = [[c[3], c[4], None, c[6], c[6], c[8], c[10], c[12]] for c in cursor.columns(table=table_name)]
+        # map T-SQL's `sp_columns` stored procedure to db-api cursor description
+        # https://docs.microsoft.com/en-us/sql/relational-databases/system-stored-procedures/sp-columns-transact-sql
+        columns = [[c[3], c[4], None, c[6], c[6], c[8], c[10], c[12]] for c in cursor.execute('exec sp_columns %s', [table_name]).fetchall()]
         items = []
         for column in columns:
             if identity_check and self._is_auto_field(cursor, table_name, column[0]):