Description:
------------
The SQL database available on Azure apparently does not have the same
connection semantics as SQL Server.  “use DATABASE” is not possible — it
returns an error saying that you should open a new connection if you
want a new database.

This is confusing when you are using the DBLIB connector because it is
the DBLIB connection code that does the “use”, not the developer's PHP
code.

The FreeTDS people recognized this a while back:

    About a year ago we added the DBSETLDBNAME macro as a way to set the
    dbname in the db-lib LOGINREC.  That sets the dbname in the login
    packet, obviating the need for "USE dbname".

    http://lists.ibiblio.org/pipermail/freetds/2012q4/028168.html

The attached patch makes use of DBSETLDBNAME and eliminates the USE.


Test script:
---------------
<?php

try {
    $server = "SERVER.database.windows.net:1433";
    $username = "USER@SERVER";
    $password = "PASSWORD";
    $dbname = "DBNAME";
    $mssql = new PDO("dblib:host=$server;dbname=$dbname",$username,$password);
    echo "Success!\n";
}
catch ( PDOException $e ) {
   print( "Error connecting to SQL Server." );
   die(print_r($e));
}