<?php 
/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */


/**
 * This class encapsulates information regarding the establishment
 * of database connection.
 */

class ConnectionInfo
{
	public $server; 	//The database server (eg: 127.0.0.1:1433)
	public $user;		//User name 
	public $password;	//Password
	public $database;	//Database name
}

/**
 * The method retrieves information for the database connection
 * from a configuration file. The name of the config file should
 * be, database_config.xml, and it should be in the same directory
 * as this file.
 * @return non NULL value (ConnectionInfo object), upon successfull 
 * execution, and NULL if some information regarding the 
 * connection is not available.
 */

function GetConnectionInfo()
{
	$doc = new DOMDocument();
	$result = $doc->load('database_config.xml');

	$server = $doc->getElementsByTagName("server")->item(0)->nodeValue;
	$user = $doc->getElementsByTagName("user")->item(0)->nodeValue;
	$password = $doc->getElementsByTagName("password")->item(0)->nodeValue;
	$database = $doc->getElementsByTagName("database")->item(0)->nodeValue;

	if ($server == NULL || $user == NULL || $password == NULL || $database == NULL)
	{
		error_log ("SERVER, USER, PASSWORD OR DATABASE IS NULL\n");
	}
	else
	{
		$ConnInfo = new ConnectionInfo();
		$ConnInfo->server = $server;
		$ConnInfo->user = $user;
		$ConnInfo->password = $password;
		$ConnInfo->database = $database;
	}
	return $ConnInfo;
}

/**
 * This method establishes a connection to the database. 
 * @return dbhandle, upon successfull execution a non null
 * handle to the database connection is returned. Else it 
 * will be null.
 */

function ConnectToDatabase()
{
	$connInfo = GetConnectionInfo();
	if ($connInfo != NULL)
	{
		$dbhandle = mssql_connect($connInfo->server, $connInfo->user, $connInfo->password)
			or die ("Couldn't connect to the server!!!");	    	
		$selected = mssql_select_db($connInfo->database, $dbhandle) 
			or die ("Couldn't open the database!!!");
	}
	return $dbhandle;
}

/**
 * This method executes a query that it receives.
 * @param query the query to execute
 * @return non-NULL upon success and NULL otherwise.
 */

function ExecuteQuery($query)
{
	return mssql_query($query);
}

/**
 * This method close the connection that is established to the
 * database.
 * @param dbhandle handle to the database
 */

function CloseDatabase($dbhandle)
{
	mssql_close($dbhandle);
}

/**
 * This method returns the a value from a mssql result set (a tuple
 * returned after execution of ExecuteQuery method.
 * @param result, the result obtained from ExecuteQuery method.
 * @param raw, the raw number
 * @param column, the column number
 * @return the value at (raw, column) of the tuple.
 */

function GetMSSQLValue($result, $raw, $column)
{
	return mssql_result($result, $raw, $column);
}
?>