anchor.diff:      {ok, C2, Rows} = execute(Conn, Stmt, Params, Stmt#stmt.stmt_type),
       {ok, C2, Stmt#stmt{rows=Rows}}.
   
  +execute(Conn, Stmt) -> execute(Conn, Stmt, []).
  +
   %% Description
   description([], XSqlVar) ->
       lists:reverse(XSqlVar);
  
positive.code:     {error, Reason, C3} ->
          {error, Reason, C3}
      end.
  
  %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
  % public functions
  
negative.code: 
  -export([connect/5, close/1, begin_transaction/2]).
  -export([allocate_statement/1, prepare_statement/3, free_statement/3, columns/1]).
  -export([execute/2, execute/3, description/1]).
  -export([commit/1, rollback/1]).
  -export([fetchone/2, fetchall/2]).
  
  