Undefined class constant 'SQLSRV_ATTR_DIRECT_QUERY'

Humm... I coded an small script just to make sure I had connection and I was able to connect using the regular PHP function mssql_connect and mssql_query. So PDO MS-SQL doesn't support MS-SQL 2000?

@ashayc thank you for the clarification.

OK, so in a nutshell I have a linux server with Drupal 7 setup and since so much advertising has been made to the new PDO support, I was thinking to use it to have an small module connect to the office MS-SQL server grab some data and display it in a page when call. That is the reason why I was using this driver.

Should I use something else?

BTW I was playing with the code and I change it to:

    // Launch the connection to the server.
    parent::__construct('sqlsrv:' . implode(';', $options), $connection_options['username'], $connection_options['password']);
    
/*
    parent::__construct('sqlsrv:' . implode(';', $options), $connection_options['username'], $connection_options['password'], array(
      PDO::SQLSRV_ATTR_DIRECT_QUERY => TRUE,
    )); 
*/ 

Now I am getting a connection, but it seems to be failing at the db_query and also at:

Uncaught exception thrown in shutdown function.

PDOException: could not find driver in db_delete() (line 2352 of /home/XXXX/public_html/includes/database/database.inc).

Once again thank you,
Emil

Here is my final working solution in case someone need it a simple way to connect to MS-SQL 2000 from Drupal 7 in Linux:

<?php
function module_page(){
	$header = array("No.","A","B","C");
	$rows = array();
	
	// Get some information from a non-Drupal database. 
	$conn = new PDO("dblib:host=192.168.1.100;dbname=YOUR_DB", 'YOUR_USERNAME', 'YOUR_PASSWORD'); 
   	$result = $conn->query("SELECT TOP 10 A, B, C FROM DDDD WHERE E>'0'");
	$a = 1;
	
	foreach ($result as $record) {
		  
		  $rows[] = array($a, $record['A'], $record['B'], $record['C']);  
		  $a++;
	}

	return theme('table', array('rows' => $rows,'header' => $header,));
}
?>

Thank you all for your time and effort.
Emil

@Jean Gionet,
I created a module where I inserted the code to display the data as a regular Drupal table. I also did for someone else reading this threat the other day a modification for a cron job using Drupal 7 to import data from MSSQL into Drupal as nodes. Here is the new code:

<?php

/**
  *  Implements hook_cron
  */
  
  function YOUR_MODULE_cron() {
  
    //  Get last process unique ID
	$last_id = variable_get('mymodule_last_id', 0);
  
    //  Stablish a connection to the remote MSSQL server
	$conn = new PDO("dblib:host=192.168.1.100;dbname=YOUR_DB", 'YOUR_USERNAME', 'YOUR_PASSWORD');
	
	//  Prepate query to execute
	$result = $conn->query('SELECT TOP 10 A, B, C FROM DDDD WHERE E>:last_id, array(':last_id' => $last_id) ');
  
    //  Loop thru the results if any
	foreach ($result as $record) {

		//  Create new node
		$node = new StdClass();
		$node->type = 'story'; // Content type
		$node->language = LANGUAGE_NONE;
		$node->uid = 1; // User ID
		node_object_prepare($node);

		$node->title = $record['A'];   // Node title

		$node->body[$node->language][0]['value']   =$record['B'];
		$node->body[$node->language][0]['summary'] = $record['C'];
		$node->body[$node->language][0]['format']  = 'filtered_html';

		//  Save new node (You might even consider destroying the node object using the unset function)
		$node = node_submit($node);
		node_save($node);
		
		//  Log new created node
        watchdog('YOUR_MODULE', 'New node created from MSSQL import %data', array('%data' => $record['A']), WATCHDOG_NOTICE, $link = NULL);

    }
  
  }
?>