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The Microsoft SQL Server ODBC driver uses the same basic mechanism to
establish connections to SQL Server as is used by applications using SQL
Server's proprietary DBLIB API. Both DBLIB clients and the Microsoft SQL
Server ODBC driver communicate to the underlying network through a SQL
Server network library. There is a network library for each of the network
protocols SQL Server can use for client/server communications. The purpose
of the network library is to take generic requests from DBLIB or the ODBC
driver and encapsulate those requests in the packets of the underlying
network. When you configure an ODBC data source for the Microsoft driver,
you must provide the driver with the same information regarding network
libraries as you provide to DBLIB applications.
The connectivity parameters for SQL Server DBLIB applications are defined
using the SQL Server Client Configuration Utility. The best description of
the parameters that must be specified in the Client Configuration Utility
is in the SQL Server version 6.0 or 6.5 "Administrator's Companion,"
Chapter 4, Configuring Clients. The basic information is also discussed in
the SQL Server 4.21a "Configuration Guide," Chapter 3, "Client Installation
and Configuration."
If you want to configure your ODBC data sources for the Microsoft SQL
Server driver, you must first understand how to manage the entries in the
Client Configuration Utility. You should first review the material
referenced above, and then use the Client Configuration Utility to define
connections and test them with the SQL Server DBLIB-based utilities, such
as ISQL/w.
You need to have the SQL Server client utilities installed on your client
to gain access to the Client Configuration Utility and the other utilities
such as ISQL/w. It is also usually necessary to install the SQL Server
client utilities if you want to use any network protocol other than named
pipes to connect to SQL Server from your ODBC application. Most products
which install the Microsoft SQL Server ODBC Driver only install the named
pipes network library; in these cases, the only way you can get the other
network libraries for SQL Server is to install the SQL Server client
utilities.
Once you understand how to define SQL Server advanced network entries
with the Client Configuration Utility, it is easy to configure ODBC
entries for the Microsoft driver. You can configure ODBC data source names
(DSNs) either by using the ODBC Administrator or calling the
SQLConfigDataSource function. There is a direct correspondence
between ODBC Administrator, SQLConfigDataSource, and Client Configuration
Utility parameters as follows:
ODBC Administrator SQLConfigDataSource Client Config Utility
------------------ ------------------- ---------------------
Server SERVER Server
Network Library NETWORK DLL
Network Address ADDRESS Connection String
It is important that data sources you define for the Win32 SQL Server
driver always reference a Win32 network library, and data sources for the
Win16 SQL Server driver always reference Win16 network libraries:
Type Driver Network Libraries
----- -------- ------------------------------------------------
Win32 SQLSRV32 DBMSSOCN, DBMSSPXN, DBMSVINN, DBMSRPCN, DBNMPNTW
Win16 SQLSRVR DBMSSOC3, DBMSSPX3, DBMSVIN3, DBMSRPC3, DBNMP3
The connection information from an ODBC data source is stored in the same
location and format as a Client Configuration Utility advanced client
entry. After you define an ODBC DSN, its connection entry will show up as
an advanced entry in the Client Configuration Utility, and DBLIB clients
could use the server name to connect to SQL Server.
There are a couple of special cases regarding the parameters for ODBC
data sources. If you want a data source that will always connect to a
server using the current default network library defined with the Client
Configuration Utility, you should specify:
Server <servername>
Network Library (default)
Network Address (default)
where <servername> is the network name of the Windows NT server running
SQL Server. Any DSN set up this way should work at sites that have not
installed the SQL Server Client Utilities because the ODBC driver will
default to the named pipes network library, which is installed by all
products that install the Microsoft driver.
If the ODBC application is on the same server as SQL Server, the following
data source will connect using local named pipes:
Server (local)
Network Library (default)
Network Address (default)
NOTE: (local) and (default) should be keyed in exactly as shown, including
the parenthesis.