ASP.Net Edit Course Code

Edit Course Cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
public partial class admin_EditCourse : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            if (Request.QueryString["cid"] == null)
            {
                Response.Redirect("~/admin/ViewCourse.aspx", true);
            }
            string cid = Request.QueryString["cid"].ToString();
            string qu = "select coursename from course where courseid=" + cid;
            DataSet ds = dbase.select(qu);
            if (ds != null && ds.Tables.Count == 1)
            {
                TextBox1.Text = ds.Tables[0].Rows[0]["coursename"].ToString();
                RequiredFieldValidator1.InitialValue = TextBox1.Text;
            }
            lblCourseId.Text = cid;
        }
    }

    protected void Button1_Click(object sender, EventArgs e)
    {
        string up = TextBox1.Text;
        string qu = "update course set coursename='"+up+"' where courseid="+lblCourseId.Text;
        int i = dbase.insert(qu);
        if (i == 1) {
        //Successful
            ScriptManager.RegisterStartupScript(this, this.GetType(), "js1",
                "alert('Saved Successfully!!');window.location='ViewCourse.aspx'", true);
          }
        else {
        //Error unsuccesful
            ScriptManager.RegisterStartupScript(this, this.GetType(), "js2",
      "alert('Error While Saving. Try Again later');window.location='ViewCourse.aspx'", true);
        }
    }
    protected void Button2_Click(object sender, EventArgs e)
    {
        Response.Redirect("~/admin/ViewCourse.aspx");
    }
}