如何在特定DataTable行的其余列中添加值？

Question

我已經使用asp.net和SQL Server為Android應用程序創建了Restful API（基於JSON的API）。 通過以下鏈接，我成功通過Restful Web服務執行了從android應用到sql服務器數據庫的CURD操作：

http://www.tutecentral.com/restful-api-for-android-part-1/

現在，我想要為2個或更多相關的sql select查詢創建單個web方法，並將結果添加到單個datatable中，即在執行第二個查詢時在datatable行的其余列中添加值。 但是當我嘗試這樣做時，我的應用程序崩潰了：

上述方案的Web Service方法是：

public DataTable GetStaffProfile(string userid)
{
    String faculty_id="";
    DataTable staffProfile = new DataTable();

   //Adding data to these columns on executing 1st sql query
    staffProfile.Columns.Add(new DataColumn("eid", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("empid", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("userid", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("fname", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("lname", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("fathername", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("dob", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("nationality", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("religion", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("cnic", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("gender", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("domicile", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("designame", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("dname", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("employmentdate", typeof(String)));

//Adding data to these columns on executing 2nd sql query
    staffProfile.Columns.Add(new DataColumn("qualification", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("university", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("majors", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("year", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("city", typeof(String)));
    staffProfile.Columns.Add(new DataColumn("country", typeof(String)));

    if (dbConnection.State.ToString() == "Closed")
    {
        dbConnection.Open();
    }
    string query = "SELECT eid, empid, userid, fname,lname, fathername, dob, nationality, religion, cnic, gender, domicile,(select title from uw_designation where desigid=uw_employee.desigid) as designame,(select dname from uw_department where "
        +"deptid=uw_employee.deptid) as dname, employmentdate FROM uw_employee where userid='"+userid+"'";
    SqlCommand command = new SqlCommand(query, dbConnection);
    SqlDataReader reader = command.ExecuteReader();
    if (reader.HasRows)
    {
        while (reader.Read())
        {
            faculty_id = reader["eid"] as string;
            staffProfile.Rows.Add(reader["eid"], reader["empid"], reader["userid"], reader["fname"], reader["lname"], reader["fathername"], reader["dob"], reader["nationality"],
                reader["religion"], reader["cnic"], reader["gender"], reader["domicile"], reader["designame"], reader["dname"],
                reader["employmentdate"]);
        }
    }
    reader.Close();


    //getting staff qualification


    string query2 = "SELECT TOP(1) eid, qualification, university, majors, year,city,country " +
                    "FROM uw_employee_education where eid='"+faculty_id+"'";
    SqlCommand command2 = new SqlCommand(query2, dbConnection);
    SqlDataReader reader1 = command2.ExecuteReader();
    if (reader1.HasRows)
    {
        while (reader1.Read())
        {
            staffProfile.Rows[0]["qualification"]=reader1["qualification"] as string;
            staffProfile.Rows[0]["university"] = reader1["university"]as string;
            staffProfile.Rows[0]["majors"] = reader1["majors"] as string;
            staffProfile.Rows[0]["year"] = reader1["year"] as string;
            staffProfile.Rows[0]["city"] = reader1["city"] as string;
            staffProfile.Rows[0]["country"] = reader1["country"] as string;
        }
    }
    reader1.Close();

    dbConnection.Close();
    return staffProfile;
}

這兩個查詢僅返回一個結果。 各種幫助都值得贊賞。 提前致謝。

Answer 1

您是否嘗試將現有的SqlCommand更改為第二個查詢。

string query2 = "SELECT TOP(1) eid, qualification, university, majors, year,city,country " +
                "FROM uw_employee_education where eid='" + faculty_id + "'";
command.CommandText = query2;
SqlDataReader reader1 = command.ExecuteReader(); 

另外，在創建SQL查詢時，請考慮使用SQL注入。 我建議您使用SqlParameter 。