将数据库数据回显到 html php pdo

Question

我在选择语句上加载 html 时有一个数据库选择，我以降序选择最后五个，或者这里是代码

加载事件.php

<?php 
function LoadEvent(){
    global $dbh;
    $stmt = $dbh->prepare("SELECT * FROM events ORDER by event_id DESC LIMIT 5") ;
    //$stmt->bindValue(1,$eventwhat);
    $stmt->execute();
    while($selected_row = $stmt->fetch(PDO::FETCH_ASSOC)){
        $_SESSION['searchresultwhat'] = $selected_row['event_what'];
        $_SESSION['searchresultwhere'] = $selected_row['event_where'];
        $_SESSION['searchresultwhen'] = $selected_row['event_when'];
        $_SESSION['searchresultwho'] = $selected_row['event_who'];
        $event = array($_SESSION['searchresultwhat'] => $selected_row['event_what'], $_SESSION['searchresultwhere'] =>$selected_row['event_where'], $_SESSION['searchresultwhen'] =>$selected_row['event_when'],$_SESSION['searchresultwho'] =>$selected_row['event_who']);
        $_SESSION['arr'] = $event;

        foreach ($_SESSION['arr'] as $_SESSION['searchresultwhat'] => $selected_row['event_what']){
            echo $_SESSION['searchresultwhat'];
            echo "<br/>\n";
        }
    }

}       
?>

我在首页的html中写了

index.php

<?php include_once("include/loadevent.php");
    LoadEvent();?>

在html中我的代码是

<?php
    foreach ($_SESSION['arr'] as $_SESSION['searchresultwhat'] => $selected_row['event_what']){
        echo $_SESSION['searchresultwhat'];
        echo "<br/>\n";
    }
?>

当我从 loadevent.php 执行回显时，我按降序获得最后五个，但在索引中，我得到的只是第一个事件，仅此而已，为什么这样任何人都可以看到我的错误在哪里？

Answer 1

您正在使用 $_SESSION 变量做一些非常奇怪的事情，据我所知，根本没有理由。试试这个：

<?php

    function LoadEvent()
    {
        global $dbh;

        $stmt = $dbh->prepare("SELECT * FROM events ORDER by event_id DESC LIMIT 5") ;
        $stmt->execute();

        $events = array();

        while ($selected_row = $stmt->fetch(PDO::FETCH_ASSOC))
        {
            $events[] = array(
                'searchresultwhat'  => $selected_row['event_what'],
                'searchresultwhere' => $selected_row['event_where'],
                'searchresultwhen'  => $selected_row['event_when'],
                'searchresultwho'   => $selected_row['event_who']
            );
        }

        // Is this just for testing? Or should it be echoing stuff all the time?
        // foreach ($events as $key => $value)
        // {
        //     echo $value['searchresultwhat'];
        //     echo "<br/>\n";
        // }

        // This is completely optional and should be removed if you don't
        // use the $_SESSION method later on in your HTML 
        $_SESSION['arr'] = $events;

        return $events;
    }
?>

...然后在您的 HTML 中执行以下操作：

<?php

    foreach ($_SESSION['arr'] as $value)
    {
        echo $value['searchresultwhat'];
        echo "<br/>\n";
    }

?>

或者，更好在你的 index.php 中这样做：

<?php

    include_once("include/loadevent.php");

?>

然后在您的 HTML 中，您可以一起避免 $_SESSION：

<?php

    foreach (LoadEvent() as $value)
    {
        echo $value['searchresultwhat'];
        echo "<br/>\n";
    }

?>

Answer 2

简单的解决方案是将$_SESSION['arr'] = $event; 替换为$_SESSION['arr'][] = $event; AND

foreach ($_SESSION['arr'] as $_SESSION['searchresultwhat'] => $selected_row['event_what']){
    echo $_SESSION['searchresultwhat'];
    echo "<br/>\n";
}

与

foreach ($_SESSION['arr'] as $value){
    echo $value[$_SESSION['searchresultwhat']];
    echo "<br/>\n";
}

Answer 3

在您的“while”循环中，您会覆盖 $_SESSION superglobal 中的值：

while($selected_row = $stmt->fetch(PDO::FETCH_ASSOC)){
    //it is overwritten each time you are in while loop
    $_SESSION['searchresultwhat'] = $selected_row['event_what'];
    (...)

    foreach ($_SESSION['arr'] as $_SESSION['searchresultwhat'] => $selected_row['event_what']){
        //in this place when you echo it, it echoes current loop iteration so it is executed 5 times
        echo $_SESSION['searchresultwhat'];
        echo "<br/>\n";
    }
}

在 index.php 中，您只能从 while 循环中回显最后一个值。