VS2010 Error in foreign key queries in Aspx.cs page

Question

I'm using VS2010. I have Doubt
    I create a database  with name of TAX, Could you please send me a sample project? Base on the scenario. I don't know how to query and create stored procedures in MS SQL.. I just want to have an overview on which tables and fields are existing as per required by our DB Admin not to alter any table or alter any fields.
  Tables  :   Fields
  employee  :  employee_no[Primary Key], lastname , firstname
           Document                 :  DocumentId[Primary Key], employee_no[Foreign  Key],Documentname,Documentpath
       using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data;
using System.Data.SqlClient;
using System.IO;


public partial class Form16UL : System.Web.UI.Page
{
    private SqlConnection con = new SqlConnection("Data Source=mani-pc;Initial Catalog=TAX;Integrated Security=True");
    protected void Page_Load(object sender, EventArgs e)
    {
       
    }
   
    protected void btnsubmit_Click(object sender, EventArgs e)
    {
        string filename = Path.GetFileName(fileUpload1.PostedFile.FileName);
        fileUpload1.SaveAs(Server.MapPath("Form/" + filename));
        con.Open();
        SqlCommand cmd = new SqlCommand("insert into Document(DocumentName,DocumentPath) values(@DocumentName,@DocumentPath)", con);


     
        cmd.Parameters.AddWithValue("@DocumentName", filename);
        cmd.Parameters.AddWithValue("@DocumentPath", "Form/" + filename);
        cmd.ExecuteNonQuery();
       
        con.Close();
        lblmsg.Text = "Thanx for uploading your form 16 file";
           


    }
}