如果用户名不存在＆QUOT; INSERT INTO＆QUOT;否则[更新＆QUOT; （显示信息） [英] If username not exist "INSERT INTO" Else "UPDATE" (display info)

问题描述

这是我的表：

<table>
    <tr><td><b>Utilizador:</b></td><td><asp:Label ID="username" runat="server"></asp:Label></td></tr> 
    <tr><td><b>Telefone da Empresa:</b></td><td><asp:TextBox ID="empresa" runat="server" MaxLength="13"></asp:TextBox> (Exemplo: [phone]xxx)</td></tr>
    <tr><td><b>2º Telefone:</b></td><td><asp:TextBox ID="empresa2" runat="server" MaxLength="4"></asp:TextBox> (Exemplo: xxxx)</td></tr>
    <tr><td><b>Telemóvel:</b></td><td><asp:TextBox ID="telemovel" runat="server" MaxLength="13"></asp:TextBox> (Exemplo: +3519xxxxxxxx)</td></tr>
    <tr><td colspan="2"><asp:Label ID="lblInfo" runat="server" Font-Bold="True"></asp:Label></td></tr>
    <tr><td><asp:Button ID="cmdSave" runat="server" Text="Guardar" onclick="cmdSave_Click" /></td><td></td></tr>
    </table>

我想验证如果的用户名在数据库中告诉我答案的更新的 ELSE 插入的

i want verify IF username exist in database show me the answers to update ELSE insert into

这是我的code后面为止。它给的插入的

this is my code behind so far. it's to insert into

    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            username.Text = "[" + HttpContext.Current.User.Identity.Name + "]"; 
        }

        protected void cmdSave_Click(object sender, EventArgs e)
        {
            string sFilePath = Server.MapPath("Database3.accdb");
            OleDbConnection Conn = new OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + sFilePath + ";Persist Security Info=False;");
            string insertCmd = "INSERT INTO colaborador(Empresa,Empresa2,Telemovel,username) VALUES (@Empresa,@Empresa2,@Telemovel,@username)";
            using (Conn)
            {
                Conn.Open();
                OleDbCommand myCommand = new OleDbCommand(insertCmd, Conn);
                myCommand.Parameters.AddWithValue("@Empresa", empresa.Text);
                myCommand.Parameters.AddWithValue("@Empresa2", empresa2.Text);
                myCommand.Parameters.AddWithValue("@Telemovel", telemovel.Text);
                myCommand.Parameters.AddWithValue("@username", HttpContext.Current.User.Identity.Name);            
                Response.Write(" ");
                myCommand.ExecuteNonQuery(); 
                lblInfo.Text = "Dados guardados!";
                lblInfo.ForeColor = System.Drawing.Color.Green;
            }
        }
}

我的目的就是之前回答我的表显示的回答问题[或显示一个消息，说用户已经回答如果在我的数据库不存在，则显示该表到现场。
它的驾驶我疯狂无法这样的事情

my purpose is before answer my table show the answered questions [or display an message saying "User already answered"] if not exist in my database then display the table to field. It's driving me crazy can't to such thing

推荐答案

这可以这样实现，

  SqlCommand objcmd = new SqlCommand("SELECT 1 from Table WHERE Username=@NAME" , objsqlconn);//get rows if username exists
cmd.Parameters.Add("@NAME", SqlDbType.NVarChar,20).Value = Master_product_txt.Text;   
objsqlconn.Open();
    readr = SelectCommand.ExecuteReader();

    if (!readr.HasRows) 
    {
    `// write Code to insert values
    }`
    else
    {
      //write code to retrieve values and update          
    }

主编的code由@阿ツ

Edited the code as pointed out by @ A ツ

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