OracleParameter 用法

public object checkUser(string userid,string password) {

            string sql = "select count(1) from T_USERINFO where s_userid=:userid and s_userpassword=:password";

            OracleParameter p1 = new OracleParameter(":userid", OracleType.VarChar,20);

            OracleParameter p2 = new OracleParameter(":password", OracleType.VarChar,20);

            p1.Value = userid;

            p2.Value = password;

            OracleParameter[] op = {p1,p2};

            return DbHelperOra.GetSingle(sql, op);

        }