Question

以下代码在限制为0时工作正常，当我将它们限制为0,30时我无法检索记录我确信我的数据库有足够的记录数。但我怀疑dr [3]之后的语法.ToString（）;如何检索所有这些。

string MyConString = "DRIVER={MySQL ODBC 3.51 Driver};" + "SERVER=localhost;" + "DATABASE=malla_softmail2;" + "UID=xxx;" + "PASSWORD=xxx;" + "OPTION=3";
        OdbcConnection MyConnection = new OdbcConnection(MyConString);
        MyConnection.Open();
        OdbcCommand cmd = new OdbcCommand("Select * from awm_test where user=? limit= 0, 1", MyConnection);
        cmd.Parameters.Add("@email", OdbcType.VarChar, 255).Value = "hello";
        OdbcDataReader dr = cmd.ExecuteReader();
        if (dr.HasRows == false)
        {
          //  throw new Exception();
        }
        if (dr.Read())
        {
            string a = dr[0].ToString();
            string b = dr[1].ToString();
            string c = dr[2].ToString();
            //string d = dr[3].ToString();
            //string f = dr[4].ToString();
            //string g = dr[5].ToString();

            Response.Write(a);
            Response.Write(b);
            Response.Write(c);
            //Response.Write(d);
            //Response.Write(f);
            //Response.Write(g);

Answer 1

您只处理查询返回的第一条记录。尝试：

while (dr.Read()) {
    string firstField = dr[0].ToString();
    string secondField = dr[1].ToString();
    string thirdField = dr[2].ToString();

    // ...
}

Answer 2

您只需要使用while(dr.Read()) {...do stuff for each row...}读取循环中的行 - 每个dr.Read()移动到下一行。

ODBC选择所有命令

2 个答案: