Insert XML Data To MySQL using PDO

xml_to_db.php

<?php
# important
@date_default_timezone_set("GMT");

# create PDO object and intialise 
$db = new PDO('mysql:host=localhost;dbname=bristol_transport;charset=utf8', 'root', '');
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$db->setAttribute(PDO::ATTR_EMULATE_PREPARES, false);

# create a simpleXML object with file as input
$xml = simplexml_load_file("transport_v1.xml");

############### POPULATE ward TABLE ##################################
# set record counter
$rec = 0;

# get a array of wards (unique now)
$wards = $xml->xpath("//ward");

# empty the ward table & reset AUTO_INCREMENT 
$stmt = $db->query('TRUNCATE TABLE ward');

# populate the ward table setting ward_id = $rec
foreach ($wards as $ward) {
	# increment record counter
	$rec++;
	
	# insert data
	$stmt = $db->prepare("INSERT INTO ward(`ward_id`, `name`, `lat`, `long`) VALUES(?, ?, ?, ?)");
	$stmt->execute(array($rec, $ward['name'], $ward['lat'], $ward['long']));
}

############### POPULATE tmode TABLE #################################
#re-set record counter
$rec = 0;

# get a array of transport modes
$modes = $xml->xpath("//ward[1]/mode");

# empty the tmode table & reset AUTO_INCREMENT 
$stmt = $db->query('TRUNCATE TABLE tmode');

# populate the tmode table setting ward_id = $rec
foreach ($modes as $mode) {
	# increment record counter
	$rec++;
	
	# insert data
	$stmt = $db->prepare("INSERT INTO tmode(`tmode_id`, `mode`) VALUES(?, ?)");
	$stmt->execute(array($rec, $mode['type']));
	
	# build up look-up array for for tmode_id
	$tmode[$rec] = $mode['type'];
}

############### POPULATE ward_tmode TABLE ############################
#re-set record counter
$rec = 0;

# get the year value
$year = $xml->xpath("/transport/@year")[0];

# empty the ward_tmode table & reset AUTO_INCREMENT 
$stmt = $db->query('TRUNCATE TABLE ward_tmode');

# populate the ward_tmode table setting id_ward = $rec & 
# using the look-up array $tmode to find id_tmode
foreach ($wards as $ward) {
	# increment record counter
	$rec++;
	
	# get a array of all mode entities in the current ward 
	$ward_modes = $xml->xpath("//ward[" . $rec . "]/mode");

	# populate table ward_tmode
	foreach ($ward_modes as $wm) {
		# look up key value for id_tmode
		$key = array_search((string) $wm['type'], $tmode); 
	
		# insert data
		$stmt = $db->prepare("INSERT INTO ward_tmode(`id_ward`, `id_tmode`, `year`, `percent`) VALUES(?, ?, ?, ?)");
		$stmt->execute(array($rec, $key, $year, $wm['percent']));
	}
}

# close db connection
$db=null;
# all done
?>