How to edit only logged in users profile information using session. In this code there are 2 users with username same but password different.when i click edit button always the first users info in...

using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Data.SqlClient;

public partial class _22 : System.Web.UI.Page
{
    SqlConnection conn = null;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (Session["user"] == null)
        {
            Response.Redirect("MainLogin.aspx");
        }
    }
    protected void Button2_Click(object sender, EventArgs e)
    {
        if (Button2.Text == "edit")
        {
            UpdateData();
        }
    }

    private void UpdateData()
    {
        // SqlConnection conn = null;
        SqlCommand cmd = null;
        try
        {
            conn = new SqlConnection(ConfigurationManager.ConnectionStrings["PConnStr"].ConnectionString);
            string sql = "Update ABC set name=@name,age=@age where name=@a";
            conn.Open();
            cmd = new SqlCommand(sql, conn);
            cmd.Parameters.AddWithValue("@name", TextBox1.Text);

            cmd.Parameters.AddWithValue("@age", TextBox2.Text);
            cmd.Parameters.AddWithValue("@a", Session["name"]);

            cmd.ExecuteNonQuery();


            Label3.Visible = true;
            Label3.Text = "Updated Successfully";
        }

        catch (Exception ex)
        {

            Label4.Text = ex.ToString();
            Label4.Visible = true;
        }
        finally
        {
            if (conn.State == ConnectionState.Open)
            {
                conn.Close();
            }
        }
    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        SqlDataAdapter da = null;
        DataSet dsUser = null;
        SqlDataReader dr;
        try
        {
            conn = new SqlConnection(ConfigurationManager.ConnectionStrings["PConnStr"].ConnectionString);
            conn.Open();
            string sql = "Select * from ABC,Login  where name=@name and Password=@pswd";
            SqlCommand cmd = new SqlCommand(sql, conn);
            cmd.Parameters.AddWithValue("@name", Session["user"]);
            cmd.Parameters.AddWithValue("@pswd", Session["pswd"]);
            //cmd.Parameters.AddWithValue("@lname",T2.Text);
            // cmd.Parameters.AddWithValue("@p_id", cmbP_id.Text);
            dr = cmd.ExecuteReader();
            if (dr.Read())
            {


                TextBox1.Text = dr[2].ToString();
                TextBox2.Text = dr[3].ToString();
                TextBox3.Text = dr[4].ToString();

            }
        }
        catch (Exception ex)
        {
            Label3.Text = ex.ToString();
            Label3.Visible = true;
        }
    }
}