SQLServer 在Visual Studio的2种连接方法

string s = "Data Source=计算机名称;initial Catalog=数据库名称;integrated Security=True"; 

string ="Data Source = 计算机名称; Initial Catalog = 数据库名称; User ID = sa; Password = 你的密码"; 

string s = "Data Source=计算机名称;Initial Catalog=数据库名称;Integrated Security=True";  //此处使用本地计算机连接方式 
SqlConnection conn = new SqlConnection(s);   //创建连接 
conn.Open();    //打开连接 
SqlCommand cmd = conn.CreateCommand(); 
cmd.CommandText = "select from T_User";   //使用命令 
SqlDataAdapter adapter=new SqlDataAdapter(cmd); 
DataTable dt=new DataTable(); 
adapter.Fill(dt); 
conn.Dispose();  //释放所以资源 
cmd.Dispose(); 
conn.Close();  //关闭连接 
string realname=""; 
string username=""; 
string mobile=""; 
string address=""; 
for (int i=0;i<dt.Rows.Count;i++) 
{ 
    realname=dt.Rows[i][3].ToString(); 
    username=dt.Rows[i][1].ToString(); 
    mobile=dt.Rows[i][4].ToString(); 
    address=dt.Rows[i][5].ToString(); 
    Console.WriteLine("姓名为{0},用户名为{1}，手机为{2},地址为{3}", realname, username, mobile, address); 
} 
Console.ReadKey(); 

string ="Data Source = 计算机名称; Initial Catalog = 数据库名称; User ID = sa; Password = 你的密码";   //使用windows身份验证 
SqlConnection conn = new SqlConnection(s); 
conn.Open(); 
SqlCommand cmd = conn.CreateCommand(); 
cmd.CommandText = "delete from T_User where Id=5"; 
cmd.ExecuteNonQuery(); 
cmd.Dispose(); 
conn.Close(); 
Console.WriteLine("删除成功"); 
Console.ReadKey(); 

string s = "Data Source=计算机名称;initial Catalog=数据库名称;integrated Security=True"; 
SqlConnection conn = new SqlConnection(s); 
conn.Open(); 
SqlCommand cmd = conn.CreateCommand(); 
cmd.CommandText = "update T_User set Card=@card where ID=3"; 
cmd.Parameters.AddWithValue("@card", "13000000000000"); 
cmd.ExecuteNonQuery(); 
cmd.Dispose(); 
conn.Close(); 
conn.Dispose(); 
Console.WriteLine("修改成功！"); 
Console.ReadKey(); 

string s = "data source=计算机名称;initial catalog=数据库名称;integrated security=true"; 
SqlConnection conn = new SqlConnection(s); 
conn.Open(); 
SqlCommand cmd = conn.CreateCommand(); 
cmd.CommandText = "insert into T_User(UserName,Password,RealName,Mobile,Address) values(@username,@password,@realname,@mobile,@address)"; 
cmd.Parameters.AddWithValue("@username", "xingxing"); 
cmd.Parameters.AddWithValue("@password", "77777"); 
cmd.Parameters.AddWithValue("@realname", "星星"); 
cmd.Parameters.AddWithValue("@mobile", 1300000000); 
cmd.Parameters.AddWithValue("@address", "河北省北京市"); 
cmd.ExecuteNonQuery(); 
cmd.Dispose(); 
conn.Close(); 
conn.Dispose(); 
Console.WriteLine("成功插入一行"); 
Console.ReadKey();