新手求帮助，我写的数据库操作类出问题了

Question

数据库dataset

Answer 1

        static public DataSet GetDataSet(string cmdText, List<OracleParameter> cmdParms)
        {
            OracleConnection conn = connection();
            DataSet dataSet = new DataSet();
            try
            {
                conn.Open();
                OracleCommand cmd = new OracleCommand();
                cmd.Connection = conn;
                cmd.Parameters.Clear();
                cmd.CommandText = cmdText;
                foreach (OracleParameter parm in cmdParms)
                    cmd.Parameters.Add(parm);
                OracleDataAdapter adapter = new OracleDataAdapter(cmd);
                adapter.Fill(dataSet);
                cmd.Parameters.Clear();
            }
            catch (Exception ee)
            {
                throw(ee);
            }
            finally
            {
                conn.Close(); //关闭连接
            }
            return dataSet;
        }

Answer 2

返回null肯定是报错了呗，会调试么哥

Answer 3

     string sql = "select * from d_user where username=:username and password=:password";
            List<OracleParameter> list = new List<OracleParameter>();
            list.Add(new OracleParameter(":username", username));
            list.Add(new OracleParameter(":password", password));这样?
     string sql = "select * from d_user where username=@username and password=@password";
            List<OracleParameter> list = new List<OracleParameter>();
            list.Add(new OracleParameter("@username", username));
            list.Add(new OracleParameter("@password", password));

Answer 4

Oracle好像是没有@的,也不用:
string sql = "select * from d_user where username=v_username and password=v_password";
List<OracleParameter> list = new List<OracleParameter>();
list.Add(new OracleParameter("v_username", username));
list.Add(new OracleParameter("v_password", password));这样看看