Last week at JumpIn Camp we spent quite a bit of time focusing on the SQL Server Driver for PHP. As developers worked to build SQL Server support into their applications, they had lots of questions about how both the SQLSRV and PDO_SQLSRV drivers work under the hood. One of the questions that came up was "When using the SQLSRV driver to execute parameterized queries, why do I have to pass parameters by reference?"

He includes a simple code example to show this passing by reference - first without it on the call to sqlsrv_prepare (and the warning message it gives) then the more correct version of passing in the past parameter by reference.

The SQL Server Driver for PHP team understands that passing parameters by reference is not ideal. [...] With that said, the team is continuing to investigate solutions that would produce expected behavior without passing parameters by reference.