How to achieve multi-level linkage of data through PHP and UniApp

How to achieve multi-level linkage of data through PHP and UniApp

Introduction:
When developing web applications and mobile applications, we often encounter the need to achieve multi-level linkage, such as provinces and municipalities selection, product classification selection, etc. This article will introduce how to use PHP and UniApp to achieve multi-level linkage of data, and give corresponding code examples.

1. Data preparation
Before starting, we first need to prepare the data required for multi-level linkage. Suppose we want to implement a selector for three-level linkage of provinces and municipalities, we need to prepare a data table for provinces and municipalities.

Province table (provinces table):
id name
1 Province 1
2 Province 2
...

City table (cities table):
id province_id name
1 1 City 1
2 1 City 2
3 2 City 3
4 2 City 4
...

region table (areas table ):
id city_id name
1 1 area 1
2 1 area 2
3 2 area 3
4 2 area 4
...

II. PHP side implementation

1. Create a PHP file named getData.php to process front-end requests and return corresponding data.

header('Content-Type: application/json;charset=utf-8');
//Connect to the database
$pdo = new PDO ('mysql:host=localhost;dbname=test', 'root', 'password');
$pdo->exec('set names utf8');

// Get province data
$provinces = $pdo->query('select * from provinces')->fetchAll(PDO::FETCH_ASSOC);

// Get the corresponding city data based on the province ID
if (isset($_GET['province_id'])) {

$provinceId = $_GET['province_id'];
$cities = $pdo->query("select * from cities where province_id = $provinceId")->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($cities);

}

// Get the corresponding regional data based on the city ID
if (isset($_GET['city_id '])) {

$cityId = $_GET['city_id'];
$areas = $pdo->query("select * from areas where city_id = $cityId")->fetchAll(PDO::FETCH_ASSOC);
echo json_encode($areas);

}
?>

2. In the UniApp project, create a page named MultiLevelLinkage to display multi-level linkage selectors .

<script></p><div class="code" style="position:relative; padding:0px; margin:0px;"><pre class='brush:php;toolbar:false;'>export default { data() { return { province: '', // 省份 city: '', // 城市 area: '', // 区域 provinces: [], // 省份数据 cities: [], // 城市数据 areas: [] // 区域数据 } }, mounted() { this.getProvinces() }, methods: { // 获取省份数据 getProvinces() { uni.request({ url: 'http://localhost/getData.php', success: (res) =&gt; { this.provinces = res.data } }) }, // 根据省份ID获取对应的城市数据 getCities(provinceId) { uni.request({ url: 'http://localhost/getData.php?province_id=' + provinceId, success: (res) =&gt; { this.cities = res.data } }) }, // 根据城市ID获取对应的区域数据 getAreas(cityId) { uni.request({ url: 'http://localhost/getData.php?city_id=' + cityId, success: (res) =&gt; { this.areas = res.data } }) }, // 省份选择器变化时的事件 onChangeProvince(event) { const index = event.detail.value this.province = this.provinces[index].name this.city = '' this.area = '' this.getCities(this.provinces[index].id) }, // 城市选择器变化时的事件 onChangeCity(event) { const index = event.detail.value this.city = this.cities[index].name this.area = '' this.getAreas(this.cities[index].id) } } }</pre><div class="contentsignin">Copy after login</div></div><p></script>

3. Summary
Through the above examples, we can see that using PHP and UniApp to achieve multi-level linkage of data It's not complicated. Through data processing on the PHP side and page writing on the UniApp side, a simple and practical multi-level linkage selector can be implemented with only a few lines of code. I hope this article can be helpful to you in realizing your needs for multi-level data linkage.

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