使用MySQL条目填充下拉列表 [英] Populating drop downs with MySQL entries

问题描述

我有一个MySQL数据库，其中包含2个表。一个是事件表，包含事件名称和其他详细信息。另一个是实例表。此表将事件表链接到场所表并添加日期，因此每行都是链接的实例活动。

I have a MySQL database that contains, amongst other things, 2 tables. One is the events table, containing event names and other details. The other is the instance table. This table links the events table to a venue table and adds a date, so each row is an instance of the linked event.

我正在制作一个活动预订表格，供这些活动内部使用。我想允许通过下拉列表选择要预订的活动。所以，我已经用事件名称填充了一个下拉列表：

I am making an event booking form for internal use for these events. I want to allow selection of the event to be booked via a dropdown list. So, I have populated one dropdown with the event names:

$qEvent = "SELECT event_name, event_id FROM events";
$rEvent = mysqli_query($dbc,$qEvent);

echo '<select>';
while ($row = mysqli_fetch_assoc($rEvent)) {
        echo '<option value="'.$row['event_id'].'">'.$row['event_name'].'</option>';
}
echo '</select>';

我现在想要做的是，对于所选事件，抓住与该事件相关的所有实例，并使用日期填充另一个下拉列表。

What I now want to do is, for the selected event, grab all the instances associated with that event, and populate another dropdown with the dates.

我可以使用PHP执行此操作，还是需要深入了解Javascript？我想我只需要一些方法来获取下拉选择的event_id值，然后根据它进行查询，但我不知道如何没有Javascript。

Can I do this with PHP, or do I need to dip into Javascript? I think I just need some way to grab the event_id value of the dropdown selection and then query based on that, but I don't know how without Javascript.

推荐答案

你应该看看Javascript或jQuery来实现你的目标。我之前已经根据我的问题使用了jQuery。它也更简单，代码更少。

You should be looking at Javascript or jQuery for achieving your goal. I've used jQuery based on my question to you earlier. It's also simpler and less code.

您的PHP：

添加ID属性 event_menu 到你的选择菜单

Add an ID attribute event_menu to your select menu

echo '<select id="event_menu">';
while ($row = mysqli_fetch_assoc($rEvent)) {
        echo '<option value="'.$row['event_id'].'">'.$row['event_name'].'</option>';
}
echo '</select>';

<div id="container_for_new_menu"></div>

使用jQuery：

$('#event_menu').on('change', function() {
    // get selected value and build data string for AJAX
    var event_selected = "event_selected="+$(this).val();

    // send the selected data to a PHP page to build the populated menu
    $.ajax({
        url : 'populate-menu.php',
        type: 'POST',
        data : event_selected,
        dataType : 'html',
        success : function(data) {
            $('#container_for_new_menu').html(data);
        }, error : function() {
            alert("Something went wrong!");
        }
    });
});

在 populate-menu.php 上，有类似的内容：

$event_selected = isset($_POST['event_selected']) ? $_POST['event_selected'] : null;

// do SQL query here based on user's selection
// making sure you validate the data in the POST request for malicious BS
// or use parameterized queries

// then build a new menu to send back
echo '<select>';
    // loop through results and build options
echo '</select>';

这个新菜单将被发回原始页面，进入 container_for_new_menu 元素。

This new menu will then be posted back to your original page into the container_for_new_menu element.

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