2

当用户在页面上的三个框中输入某些值时，我有将数据插入表中的代码。

这些框是订单号、总重量和跟踪参考。

我现在需要向此代码添加更多功能并首先检查订单号是否存在，如果存在我需要更新列，如果不需要我需要插入新行并向其中添加数据。

我的想法很简单，比如 IF results = 0, Insert NEW, ELSE update

我怎样才能修改我的代码来做到这一点？

protected void Page_Load(object sender, EventArgs e)
{
    errorLabel.Visible = false;
    successLabel.Visible = false;
    errorPanel.Visible = false;
}

protected void submitBtn_Click(object sender, EventArgs e)
{
    if (Page.IsValid)
    {
        int _orderID = Convert.ToInt32(orderID.Text);
        string _trackingID = trackingNumber.Text;
        DateTime _date = DateTime.UtcNow;
        int _weightID = Convert.ToInt32(weightID.Text);

        SqlConnection myConnection = new SqlConnection("Data Source=localhost\\Sqlexpress;Initial Catalog=databasename;User ID=username;Password=password");
        SqlCommand myCommand = new SqlCommand("INSERT into Shipment (TrackingNumber, OrderId, ShippedDateUtc, CreatedOnUtc, TotalWeight) VALUES (@tracking, @order, @date, @date, @weight)", myConnection);

        try
        {
            myConnection.Open();
            myCommand.Parameters.AddWithValue("@order", _orderID);
            myCommand.Parameters.AddWithValue("@tracking", _trackingID);
            myCommand.Parameters.AddWithValue("@date", _date);
            myCommand.Parameters.AddWithValue("@weight", _weightID);
            int rowsUpdated = myCommand.ExecuteNonQuery();
            myConnection.Close();
            if (rowsUpdated > 0)
            {
                alertdiv.Attributes.Add("class", "alert alert-success form-signin");
                successLabel.Text = "Thank you, tracking details have been updated";
                successLabel.Visible = true;
                errorPanel.Visible = true;

            }
            else
            {

                alertdiv.Attributes.Add("class", "alert alert-error form-signin");
                errorLabel.Text = "Oh dear, the order number is not recognised, please check and try again";
                errorLabel.Visible = true;
                errorPanel.Visible = true;
            }

            orderID.Text = "";
            trackingNumber.Text = "";
            weightID.Text = "";
        }
        catch (Exception f)
        {
            errorLabel.Text = "This order number does not exist, please check";
            errorLabel.Visible = true;
            errorPanel.Visible = true;
            return;

        }
    }
}

protected void Signout_Click(object sender, EventArgs e)
{
    FormsAuthentication.SignOut();
    Response.Redirect("Login.aspx");
}
4

2 回答 2

8

您可以在语句之前添加一些SELECT查询INSERT。因此，如果SELECT查询返回多于一行，则意味着您已经在数据库中拥有该记录，需要更新。所以，一般来说它会像

SqlCommand cmdCount = new SqlCommand("SELECT count(*) from Shipment WHERE OrderId = @order", myConnection);
cmdCount.Parameters.AddWithValue("@order", _orderID);
int count = (int)cmdCount.ExecuteScalar();

if (count > 0)
{
     // UPDATE STATEMENT
     SqlCommand updCommand = new SqlCommand("UPDATE Shipment SET TrackingNumber = @tracking, ShippedDateUtc = @date, TotalWeight = @weight", myConnection);
     updCommand.Parameters.AddWithValue("@order", _orderID);
     updCommand.Parameters.AddWithValue("@tracking", _trackingID);
     updCommand.Parameters.AddWithValue("@date", _date);
     updCommand.Parameters.AddWithValue("@weight", _weightID);
     int rowsUpdated = myCommand.ExecuteNonQuery();
}
else
{
     // INSERT STATEMENT
     SqlCommand insCommand = new SqlCommand("INSERT into Shipment (TrackingNumber, OrderId, ShippedDateUtc, CreatedOnUtc, TotalWeight) VALUES (@tracking, @order, @date, @date, @weight)", myConnection);
     insCommand.Parameters.AddWithValue("@order", _orderID);
     insCommand.Parameters.AddWithValue("@tracking", _trackingID);
     insCommand.Parameters.AddWithValue("@date", _date);
     insCommand.Parameters.AddWithValue("@weight", _weightID);
     int rowsUpdated = myCommand.ExecuteNonQuery();
}

编辑： 或更短：

SqlCommand command;

if (count > 0)
{
     command = new SqlCommand("UPDATE Shipment SET TrackingNumber = @tracking, ShippedDateUtc = @date, TotalWeight = @weight WHERE OrderId = @order", myConnection);
}
else
{
     command = new SqlCommand("INSERT into Shipment (TrackingNumber, OrderId, ShippedDateUtc, CreatedOnUtc, TotalWeight) VALUES (@tracking, @order, @date, @date, @weight)", myConnection);
}

command.Parameters.AddWithValue("@order", _orderID);
command.Parameters.AddWithValue("@tracking", _trackingID);
command.Parameters.AddWithValue("@date", _date);
command.Parameters.AddWithValue("@weight", _weightID);
int rowsUpdated = command.ExecuteNonQuery();
于 2013-10-25T10:00:04.213 回答
3

最有效的方法是将功能放入存储过程中，例如（伪代码）： IF EXISTS(SELECT * FROM Orders WHERE OrderNo = @orderNo) UPDATE ...

ELSE INSERT ...

如果您无法创建新的存储过程，您也可以创建一个包含此语句的命令，尽管可读性通常更差。
这两种方法都只需要一个 DB 请求。

于 2013-10-25T10:05:23.587 回答