SQL Server Browsing Example

The following example shows how SQLBrowseConnect might be used to browse the connections available with a driver for SQL Server. First, the application requests a connection handle:

SQLAllocHandle(SQL_HANDLE_DBC, henv, &hdbc);  

Next, the application calls SQLBrowseConnect and specifies the SQL Server driver, using the driver description returned by SQLDrivers:

SQLBrowseConnect(hdbc, "DRIVER={SQL Server};", SQL_NTS, BrowseResult,  
                  sizeof(BrowseResult), &BrowseResultLen);  

Because this is the first call to SQLBrowseConnect, the Driver Manager loads the SQL Server driver and calls the driver's SQLBrowseConnect function with the same arguments it received from the application.

The driver determines that this is the first call to SQLBrowseConnect and returns the second level of connection attributes: server, user name, password, application name, and workstation ID. For the server attribute, it returns a list of valid server names. The return code from SQLBrowseConnect is SQL_NEED_DATA. Here is the browse result string:

"SERVER:Server={red,blue,green,yellow};UID:Login ID=?;PWD:Password=?;  
   *APP:AppName=?;*WSID:WorkStation ID=?;"  

Each keyword in the browse result string is followed by a colon and one or more words before the equal sign. These words are the user-friendly name that an application can use to build a dialog box. The APP and WSID keywords are prefixed by an asterisk, which means they are optional. The SERVER, UID, and PWD keywords are not prefixed by an asterisk; values must be supplied for them in the next browse request string. The value for the SERVER keyword may be one of the servers returned by SQLBrowseConnect or a user-supplied name.

The application calls SQLBrowseConnect again, specifying the green server and omitting the APP and WSID keywords and the user-friendly names after each keyword:

SQLBrowseConnect(hdbc, "SERVER=green;UID=Smith;PWD=Sesame;", SQL_NTS,  
                  BrowseResult, sizeof(BrowseResult), &BrowseResultLen);  

The driver attempts to connect to the green server. If there are any nonfatal errors, such as a missing keyword-value pair, SQLBrowseConnect returns SQL_NEED_DATA and remains in the same state as it was prior to the error. The application can call SQLGetDiagField or SQLGetDiagRec to determine the error. If the connection is successful, the driver returns SQL_NEED_DATA and returns the browse result string:

"*DATABASE:Database={master,model,pubs,tempdb};  
   *LANGUAGE:Language={us_english,Franais};"  

Because the attributes in this string are optional, the application can omit them. However, the application must call SQLBrowseConnect again. If the application chooses to omit the database name and language, it specifies an empty browse request string. In this example, the application chooses the pubs database and calls SQLBrowseConnect a final time, omitting the LANGUAGE keyword and the asterisk before the DATABASE keyword:

SQLBrowseConnect(hdbc, "DATABASE=pubs;", SQL_NTS, BrowseResult,  
                  sizeof(BrowseResult), &BrowseResultLen);  

Because the DATABASE attribute is the final connection attribute required by the driver, the browsing process is complete, the application is connected to the data source, and SQLBrowseConnect returns SQL_SUCCESS. SQLBrowseConnect also returns the complete connection string as the browse result string:

"DSN=MySQLServer;SERVER=green;UID=Smith;PWD=Sesame;DATABASE=pubs;"  

The final connection string returned by the driver does not contain the user-friendly names after each keyword, nor does it contain optional keywords not specified by the application. The application can use this string with SQLDriverConnect to reconnect to the data source on the current connection handle (after disconnecting) or to connect to the data source on a different connection handle. For example:

SQLDriverConnect(hdbc, hwnd, BrowseResult, SQL_NTS, ConnStrOut,  
                  sizeof(ConnStrOut), &ConnStrOutLen, SQL_DRIVER_NOPROMPT);