带有回复的PHP MySQL评论系统

2024-06-02 • 问答

我有能够捕获初始评论和第一级答复的代码，但似乎无法捕获对答复的答复。我知道它需要使用某种形式的递归的不确定代码，但还不确定如何正确实现它。这是我的phpMyAdmin表的样子：

id名称评论reply_id
1 BigBadProducer1我爱这个vst！我用它所有的时间！ 0
2 DrummaBoy504嗨，这是Drum Squad的Drumma！ 0
3 Mike Smith您是如何使vst听起来如此出色的... 1
4 BigBadProducer1是的，我了解了如何通过YouTube Mike S ... 3对其进行调整。
5 SmoothBeatz3 Dude，我一直在寻找像这样的vst来做... 0
6 FanBoy123 Hey Drumma，您打算什么时候发行新专辑？2
7 Mike Johnson Hey Fanboy123，你为什么那么喜欢Drum S ... 6

代码如下：

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1.0">
    <meta http-equiv="x-ua-compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
<?php
// Create connection
$conn = new mysqli('localhost','root','mypassword','commentsystem2');

$sql1 = "SELECT * FROM comments WHERE reply_id = 0";
$result1 = mysqli_query($conn,$sql1);

while ($comment = mysqli_fetch_array($result1)) {
    $id = $comment['id'];
    $name = $comment['name'];
    $comment = $comment['comment'];
    
echo '
<div class="comments" style="position:relative; margin:auto; width:500px; border:1px solid black; margin-top:1px;">
<div>'.$name.'</div>
<div>'.$comment.'<br><br></div>
</div>
';

$sql2 = "SELECT * FROM comments WHERE reply_id = $id";
$result2 = mysqli_query($conn,$sql2);
while ($reply = mysqli_fetch_array($result2)) {
$id_reply = $reply['id'];
$reply_name = $reply['name'];
$reply_comment = $reply['comment'];
$reply_id = $reply['reply_id'];


echo '
<div class="replies" style="position:relative; margin:auto; width:500px; border:1px solid black; margin-top:1px;">
<div style="width:80%; text-align:center;">'.$reply_name.' replied to '.$name.'</div>
<div style="width:80%; text-align:center;">'.$reply_comment.'<br><br></div>
</div>
';

 }//end of replies while loop

}//end of comments while loop

?>
</body>
</html>

递归

这是递归解决方案的快速示例，它使用数组作为数据库查询的模型。

一些重要说明：

注意结构：所有数据获取和操作都在打印出一件东西之前完成。
作为一个对象，这会更好，它可以避免使用函数内的GLOBAL标签，但是这可以使您指向该方向。
在某些情况下，递归函数应该始终进行测试以停止递归。这个例子不行！您可以使用静态变量来计算递归并在达到一定限制时停止。

<?php

// mock data of "select * from comments"
$dbRows = [
  1 => ['name' => 'BigBadProducer1','comment' => 'I love this vst! I use it all the time!','reply_id' => 0],2 => ['name' => 'DrummaBoy504','comment' => 'Hey,this is Drumma from Drum Squad!',3 => ['name' => 'Mike Smith','comment' => 'How did you get the vst to sound so good like that...','reply_id' => 1],4 => ['name' => 'BigBadProducer1','comment' => 'Yes,I learned how to tweak it from YouTube Mike S...','reply_id' => 3],5 => ['name' => 'SmoothBeatz3','comment' => 'Dude,Ive been looking for a vst like this for a l...',6 => ['name' => 'FanBoy123','comment' => 'Hey Drumma,when are you going to release a new hi...','reply_id' => 2],7 => ['name' => 'Mike Johnson','comment' => 'Hey Fanboy123,why are you such a fanboy of Drum S...','reply_id' => 6],];

// mock data of "select id from comments where reply_id=?"
$children = [];
foreach($dbRows as $id => $row) {
  $reply_id = $row['reply_id'];
  $children[$reply_id][] = $id;
}

// format row into html
function formatRow($row,$reply_name='unknown') {
    $out =<<<FORMATROW
<div class="replies" style="position:relative; margin:auto; width:500px; border:1px solid black; margin-top:1px;">
<div style="width:80%; text-align:center;">{$row['name']} replied to {$reply_name}</div>
<div style="width:80%; text-align:center;">{$row['comment']}<br><br></div>
</div>
FORMATROW;

    return $out;
}

// mock of database CRUD function "select * from comments where id=?"
function find($id) {
    global $dbRows;
    if(array_key_exists($id,$dbRows)) {
        return $dbRows[$id];
    }
}

// mock of database CRUD function "select id from comments where reply_id=?"
function findChildren($id) {
    global $children;
    if($id == 0) { return []; }

    $out = [];
    if(array_key_exists($id,$children)) {

        $out = $children[$id];
    }
    return $out;
}

function getRepliesTo($id) {

    // test to end recursion
    // if(!$id) { return; }

    // get parent name
    $row = find($id);
    $parent_name = $row['name'];

    // start indented list every time a traversal is called
    $out = "<ul>\n";

    // list of child ids. if no children are found,// assigns an empty array so that foreach won't barf
    $children = findChildren($id);

    foreach($children as $cid) {

        // if there are children,capture their reply and then call this same function to get replies to this reply            
        if($reply= find($cid)) {
            $out .= '  <li>' . formatRow($reply,$parent_name);
            $out .= getRepliesTo($cid);
            $out .= "</li>\n";
        }
    }

    $out .= "</ul>\n";
    return $out;
}

// print_r(find(1));
// print_r(findChildren(1));
// print_r(findChildren(2));
// print traverse(1);

$id = 1; // $id = (int)$_GET['id'];

$commentData = find($id);
$replyHtml = getRepliesTo($id);

?>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width,initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
</head>
<body>
  <div class="comments" style="position:relative; margin:auto; width:500px; border:1px solid black; margin-top:1px;">
    <div><?= $commentData['name'] ?></div>
    <div><?= $commentData['comment'] ?><br><br></div>
  </div>
  <?= replyHtml ?>
</body>
</html>

材料化路径

另一种方法是使用实体化路径查询，这将需要对reply_id字段进行一些更改：

$dbRows = [
  1 => ['name' => 'BigBadProducer1','reply_id' => '/0/1'],'reply_id' => '/0/2'],'reply_id' => '/0/1/3'],'reply_id' => '/0/1/3/4'],'reply_id' => '/0/5'],'reply_id' => '/0/2/6'],'reply_id' => '/0/2/6/7'],];

想找到2的所有后代吗？ select * from comments where reply_id like '/0/2%'

带有回复的PHP MySQL评论系统

baoyixinger 回答：带有回复的PHP MySQL评论系统

递归

材料化路径

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