哪位有对数据库查询和修改，浏览的例子，贴出来看看

///////////////////////////刚修改，因该没有错误
using System;
using System.Data;
using System.Data.SqlClient;namespace SQLServerProvider
{
/// <summary>
/// Class1 的摘要说明。
/// </summary>
class Class1
{
/// <summary>
/// 应用程序的主入口点。
/// </summary>
[STAThread]
static void Main(string[] args)
{
string ConStr = @"server = (local)\yoursql;"+"Integrated Security = true;database = Northwind";
SqlConnection sqlConn = new SqlConnection(ConStr);
try
{
sqlConn.Open();
string SQL = "SELECT * FROM Employees WHERE"+
                                                  "Country = 'UK'";
                                     SqlDataAdapter da = new  SqlDataAdapter ();
  SqlCommand sqlComm = new SqlCommand(SQL,sqlConn);                               da.SelectCommand = sqlComm ;
                               DataSet ds = new DataSet();
                               da.Fill(ds,"Employees");
                               dt.Rows[0]["FirstName"] = "My New Name";//修改数据                              foreach(DataRow r in dt.Rows)
                              {
                                  Console.WriteLine("{0} \t{1}\t {2}",
                                     r["FirstName"],r["LastName"],r["City"]);
                                   Console.ReadLine();
                               }
                      SqlCommandBuilder sqlcb = new SqlCommandBuilder (da);
                      da.Update(ds,"Employees");//更新数据库

}
catch(Exception ex)
{
Console.WriteLine("Error:"+ex.Message);
} finally
{
sqlConn.Close();
Console.ReadLine();
}
     }
}
}