Understanding “Data Source=(local)” in SQL Server Connection Strings

re: Understanding “Data Source=(local)” in SQL Server Connection Strings

Soczo Zsolt — Tue, 23 Sep 2008 18:03:58 GMT

And what's the difference between (local), ., localhost and machine name?

Are they use the same protocol, or (local) and . use shared memory and localhost and machine name use tcp/ip?

re: Understanding “Data Source=(local)” in SQL Server Connection Strings

SQL Protocols — Wed, 24 Sep 2008 04:12:26 GMT

For clients shipped with SQL Server 2005 and beyond, all of (local), ., and localhost are equivalent and are not tied to any particular protocol. You can verify this for yourself pretty easily if you have a local SQL Server 2005 instance with both TCP and Shared Memory enabled:

C:\>osql -E -Stcp:(local)

1> select net_transport from sys.dm_exec_connections where session_id = @@SPID

2> go

net_transport

----------------------------------------

TCP

C:\>osql -E -Slocalhost

1> select net_transport from sys.dm_exec_connections where session_id = @@SPID

2> go

net_transport

----------------------------------------

Shared memory

Machine name is slightly different from those, since depending on the network transport protocol, we may have to do a DNS lookup to resolve it to an IP Address. You can still get shared memory from using the local machine name, though:

C:\>osql -E -SLocalMachineName

1> select net_transport from sys.dm_exec_connections where session_id = @@SPID

2> go

net_transport

----------------------------------------

Shared memory

rerro

Md.Meraj — Sat, 03 Jan 2009 16:10:41 GMT

Unable To Connect Remote Connection when my asp.net website hosting after that when user logining then it will pass the error message.

Code Behind---------

SqlConnection con = new SqlConnection();

// con.ConnectionString = "Data Source=.\\SQLEXPRESS;AttachDbFilename=|DataDirectory|\\SiliguriNeuro.mdf;Integrated Security=True;User Instance=True";

con.ConnectionString = "Data Source=.\\SQLEXPRESS,1433;AttachDbFilename=|DataDirectory|\\SiliguriNeuro.mdf;Initial Catalog=SiliguriNeuro;Integrated Security=SSPI;User ID=nrhalder;Password=12345678;";

// con.ConnectionString = "Data Source={0};User ID={1};Password={2}";

con.Open();

string UserName = TextBox1.Text;

string Password = TextBox2.Text;

// Class1.UserType = TextBox1.Text;

// Class2.UserId = UserName.ToString();

SqlDataReader dr;

string str = "select * from Login where UserName='" + UserName + "' and Password='" + Password + "'";

SqlCommand cmd = new SqlCommand(str, con);

dr = cmd.ExecuteReader();

if (dr.HasRows)

{

Server.Transfer("PatientDetails.aspx");

}

else

Label6.Text = "You are not a Valid User";

please help me

re: Understanding “Data Source=(local)” in SQL Server Connection Strings

Sam — Fri, 09 Jan 2009 23:35:17 GMT

I've got a 2 node 2005 cluster. Is there a way to make local work on it. I'm assuming it's trying to connect to the local default instance on the machine, which would be myclusterNode1 - obviously not going to work, as it needs to be going to the virtual SQL name.

Thanks

Sam

re: Understanding “Data Source=(local)” in SQL Server Connection Strings

SQL Protocols — Wed, 14 Jan 2009 21:07:12 GMT

Sam,

When connecting to cluster instances, you cannot use (local) and must use the virtual server name, please refer to my other blog for details:

http://blogs.msdn.com/sql_protocols/archive/2005/12/05/500013.aspx

Thanks,

Xinwei

re: Understanding “Data Source=(local)” in SQL Server Connection Strings

csjones — Tue, 14 Jul 2009 03:52:10 GMT

Great blogs! Keep up the good work :)