我从SQL数据库中提取信息，并通过PHP将其形成XML。我正试图使我的XML格式如下：
<channel>
<channel_name>ASN</channel_name>
<program id="1">
<title>The Simpson</title>
<info>Melfi considers turning to Homer for help...</info>
<season>S01</season>
<episode>E09</episode>
...
<channel>ASN</channel>
</program>
</channel>
<channel>
<channel_name>NBC</channel_name>
<program id="2">
<title>The Simpson</title>
<info>Melfi considers turning to Homer for help...</info>
<season>S02</season>
<episode>E04</episode>
...
<channel>NBC</channel>
</program>
</channel>
...etc
这是我的PHP，它试图模仿上面的XML结构：
<?php
header('Content-Type: application/xml; charset=utf-8');
include_once "db_connect.php";
//SQL Query
$program_sql = <<<SQL
SELECT * FROM Programs
SQL;
if ($result = $db->query($program_sql)) {
/* fetch associative array */
while ($row = mysqli_fetch_assoc($result)) {
//Data
#Descriptions
$program_title = $row['program_title'];
$program_id = $row['program_id'];
$program_info = $row['program_info'];
#Guides
$program_season = $row['program_season'];
$program_episode = $row['program_episode'];
$program_genre = $row['program_genre'];
#Times
$program_duration_hours = $row['program_duration_hours'];
$program_duration_mins = $row['program_duration_mins'];
$program_day = $row['program_day'];
$program_time_start = $row['program_time_start'];
$program_time_end = $row['program_time_end'];
#Assets
$program_image_fullsize = $row['program_image_fullsize'];
$program_image_thumbnail = $row['program_image_thumbnail'];
#Channel
$channel .= $row['channel'];
//XML Output
$output .= "<program id='".$program_id."'>
<title>".$program_title."</title>
<info>".$program_info."</info>
<season>S".$program_season."</season>
<episode>E".$program_episode."</episode>
<duration>
<hours>".$program_duration_hours."</hours>
<minutes>".$program_duration_mins."</minutes>
</duration>
<day>".$program_day."</day>
<time>
<start>".$program_time_start."</start>
<end>".$program_time_end."</end>
</time>
<genre>".$program_genre."</genre>
<image>
<fullsize>/images/program_images/".$program_image_fullsize."</fullsize>
<thumbnail>/images/program_images/thumbnails/".$program_image_thumbnail."</thumbnail>
</image>
<channel>".$channel."</channel>
</program>";
}//Channel While Loop
}//if
echo $output;
mysqli_close($db);
?>
我的PHP目前只输出程序节点；我该如何将它们包装在相应的频道标签中？
试试这个。
$rows = [
['channel_name' => 'ASN', 'program_id' => 1, 'program_title' => 'Program 1'],
['channel_name' => 'ASN', 'program_id' => 2, 'program_title' => 'Program 2'],
['channel_name' => 'NBC', 'program_id' => 3, 'program_title' => 'Program 3'],
];
// pre grouping pattern
$grouped = array_reduce($rows, function($channels, $row) {
if (!array_key_exists($row['channel_name'], $channels)) {
$channels[$row['channel_name']] = [];
}
$channels[$row['channel_name']][] = $row;
return $channels;
}, []);
foreach ($grouped as $channelName => $program) {
// build up XML
}
// Or SimpleXML pattern
$root = new SimpleXMLElement('<root />');
foreach ($rows as $row) {
$channel = $root->xpath("/root/channel/channel_name[text()='{$row['channel_name']}']/parent::node()");
if (count($channel) === 0) {
$channel = $root->addChild('channel');
$channel->addChild('channel_name', $row['channel_name']);
} else {
$channel = $channel[0];
}
$program = $channel->addChild('program');
$program->addAttribute('id', $row['program_id']);
$program->addChild('title', $row['program_title']);
}
echo $root->asXML();