<?php

			function cleanDB() {

				$sv_name = "";
				$username = "";
				$password = "";
				$db_name = "";

				$con = mysql_connect($sv_name, $username, $password) or die(mysql_error());
				mysql_select_db($db_name, $con) or die(mysql_error());
				$table = "uni_subjects";


				// 1. delete all entries that are DELETED
				$query = "SELECT * FROM " . $table;
				$result = mysql_query($query, $con) or die(mysql_error());
				while($row = mysql_fetch_array($result))
				{
					if ($row['name'] == "DELETED") {
						$querydelete = "DELETE FROM " . $table . " WHERE id = " . $row['id'];
						mysql_query($querydelete, $con) or die(mysql_error());
					}
				}



				// 2. check number of remaining subjects ($numofsubs)
				$query = "SELECT * FROM " . $table;
				$result = mysql_query($query, $con) or die(mysql_error());
				$x = 1;
				while($row = mysql_fetch_array($result))
				{
					if ($row['name'] == "DELETED") {
						$querydelete = "DELETE FROM " . $table . " WHERE id = " . $row['id'];
						mysql_query($querydelete, $con) or die(mysql_error());
					}
					$x++;
				}
				$numofsubs = $x;



				// 3. order remaining subject entries properly
					// 3.1. for $i<$numofsubs
					// 3.2. query in each loop, setting ID of next entry to $i
				for ($i=1; $i<$numofsubs; $i++) {

					$query = "SELECT * FROM " . $table;
					$result = mysql_query($query, $con) or die(mysql_error());
					$x = 1;
					while($row = mysql_fetch_array($result))
					{
						if ($x == $i && $i != $row['id']) {
							// set rowID to $i
							$queryupdate = "UPDATE " . $table . " SET id = " . $i . " WHERE id = " . $row['id'];
							mysql_query($queryupdate, $con) or die(mysql_error());
						}
						$x++;
					}
				}


			}
    ?>