CREATE PROCEDURE USR_ADD (
    login varchar( 50 ),
    pwd varchar( 255 ))
returns (
    ok char( 1 ))
as
begin
    if(not exists(select login from users where login = upper(:login))) then begin
            insert into users values
            (
                upper(:login),
                :pwd
            );
            ok = 't';
            end
    else ok = 'f';
    post_event('update_users');
    suspend;
end^

public char RunProcedure(
                String storedProcName, 
                params IDataParameter[] parameters)
        {
            char result;

            myConnection.Open();
            FbCommand command = BuildIntCommand(storedProcName, parameters);
            command.Parameters.Add("OK",FbDbType.Char).Direction = ParameterDirection.ReturnValue;
            command.CommandType = CommandType.StoredProcedure;
            result = (char)(command.Parameters["OK"].Value);
            myConnection.Close();
            return result;
        }

ok = db.RunProcedure(
					"USR_ADD",
					new FbParameter("LOGIN",login),
					new FbParameter("PWD",EncodePassword(pwd)));
				if(ok == 't') return true;
				else return false;

result = (char)(command.Parameters["OK"].Value);