Tài liệu Using an IP Address to Connect to SQL Server pdf

[ Team LiB ]Recipe 1.6 Using an IP Address to Connect to SQL Server Problem You want to connect to a SQL Server using its IP address instead of its server name.. The sample code contai

[ Team LiB ]

Recipe 1.6 Using an IP Address to Connect to SQL Server

Problem

You want to connect to a SQL Server using its IP address instead of its server name

Solution

Use the Network Address and Network Library attributes of the connection string The sample code contains a single event handler:

Connect Button.Click

Creates and opens a connection to a SQL Server using its IP address Information about the SQL Server is displayed from the properties of the SqlConnection object

The C# code is shown in Example 1-5

Example 1-5 File: ConnectSqlServerIpAddressForm.cs

// Namespaces, variables, and constants

using System;

using System.Data.SqlClient;

//

private void connectButton_Click(object sender, System.EventArgs e)

{

String connString =

"Network Library=dbmssocn;Network Address=127.0.0.1

;" +

"Integrated security=SSPI;Initial Catalog=Northwind";

SqlConnection conn = new SqlConnection(connString);

conn.Open( );

// Return some information about the server

resultTextBox.Text =

"ConnectionState = " + conn.State + Environment.NewLine +

"DataSource = " + conn.DataSource + Environment.NewLine +

"ServerVersion = " + conn.ServerVersion + Environment.NewLine;

conn.Close( );

resultTextBox.Text += "ConnectionState = " + conn.State;

}

Discussion

SQL Server network libraries are dynamic-link libraries (DLLs) that perform network operations required for client computers and SQL Server computers to communicate A server can monitor multiple libraries simultaneously; the only requirement is that each network library to be monitored is installed and configured

Available network libraries for SQL Server 2000 include:

AppleTalk ADSP

Allows Apple Macintosh to communicate with SQL Server using native

AppleTalk protocol

Banyan VINES

Supports Banyan VINES Sequenced Packet Protocol (SPP) across Banyan VINES

IP network protocol

Multiprotocol

Automatically chooses the first available network protocol to establish a

connection generally with performance comparable to using a native network library TCP/IP Sockets, NWLink IPX/SPX, and Named Pipes are supported Named Pipes

Interprocess communication (IPC) mechanism provided by SQL Server for

communication between clients and servers

NWLink IPX/SPX

The native protocol of Novell Netware networks

TCP/IP Sockets

Uses standard Windows sockets to communicate across the TCP/IP protocol Clustered installations of SQL Server support only Named Pipes and TCP/IP protocols AppleTalk, Banyan Vines, and Multiprotocol protocols are unavailable if named

instances are installed on the server

For more information about network libraries and configuring network libraries, see Microsoft SQL Server Books Online

The use of the SQL Server TCP/IP Sockets improves performance and scalability with high volumes of data It avoids some security issues associated with named pipes As with any protocol, the client and the server must be configured to use TCP/IP

To connect to SQL Server using an IP address, the TCP/IP network library must be used

to connect to the SQL Server This is done by specifying the library in the connection

string as either the attribute Net or Network Library with a value of dbmssocn Specify

the IP address using the Data Source, Server, Address, Addr, or Network Address

parameter The following connection string demonstrates using an IP address to specify the data source:

Network Library=dbmssocn;Network Address=127.0.0.1;

Integrated security=SSPI;Initial Catalog=Northwind

In the example, the IP address is the local machine This could also be specified as

(local) To specify a SQL Server other than a local instance, specify the IP address of the computer on which SQL Server is installed

Default instances of SQL Server listen on port 1433 Named instances of SQL Server dynamically assign a port number when they are first started The example above does not specify the port number and therefore uses the default port 1433 of the SQL Server If the SQL Server is configured to listen on another port, specify the port number following the IP address specified by the Network Address attribute separated by a comma as

shown in the following snippet, which connects to a local SQL Server listening on port 1450:

Network Address=(local),1450

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