How to connect SQL server to webamtrix and (execute query) using PHP

Hi,Im using webmatrix2 and SQLserver 2012 and I have the next problem:

I follewed this link   to connect SQl server with webmatrix2 and it worked just fine, but now I have a problem  I dont know how to execute a query using PHP cause I dont know how to use the connection string which its in the XML web.config file, that webmatrix just created.

Web.config

<?xmlversion="1.0"encoding="UTF-8"?><configuration><connectionStrings><addconnectionString="server=.\SQLEXPRESS;trusted_connection=True;database=LAB2"name="LAB2"providerName="System.Data.SqlClient"/></connectionStrings></configuration>

I want to know how to use this string connection to make querys using PHP. In the past without webmatrix2 I used these lines to make a connection, but know i want to know how to use this string of webmatrix

$serverName = ".\SQLEXPRESS";
$connectionInfo = array( "Database"=>"databasename");
$conn = mssqsl_connect($serverName, $connectionInfo);

btw the above code doesnt work in webmatrix cause the PHP5.3 of IIS express doesnt have the mssql dll

I hope you can help me.