How to get database data in html

How to use HTML to obtain database data

Introducing the database

In HTML, the database cannot be accessed directly. Requires the use of backend technologies such as PHP, JavaScript, or Python to fetch data from the database.

Using PHP

PHP is a popular backend language that makes it easy to connect to databases. Here is a sample code:

<code class="php"><?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";

// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);

// 检查连接
if ($conn->connect_error) {
  die("连接失败: " . $conn->connect_error);
}

// 准备查询
$sql = "SELECT * FROM table_name";

// 执行查询
$result = $conn->query($sql);

// 检索数据
while ($row = $result->fetch_assoc()) {
  echo $row["column_name"];
}

// 关闭连接
$conn->close();
?></code>

Using JavaScript

JavaScript can also use AJAX (Asynchronous JavaScript and XML) to get data from the database. The following is a sample code:

<code class="javascript">function getData() {
  // 创建 XMLHttpRequest 对象
  var xhr = new XMLHttpRequest();

  // 打开连接
  xhr.open("GET", "get_data.php", true);

  // 设置回调函数
  xhr.onload = function() {
    // 服务器响应后执行
    if (xhr.status === 200) {
      // 解析 JSON 响应
      var data = JSON.parse(xhr.responseText);

      // 输出数据
      for (var i = 0; i < data.length; i++) {
        console.log(data[i].column_name);
      }
    }
  };

  // 发送请求
  xhr.send();
}</code>

Using Python

Python can also use web frameworks such as Flask to get data from the database. Here is a sample code:

<code class="python">from flask import Flask, render_template, request

app = Flask(__name__)

@app.route('/')
def index():
  # 连接数据库
  conn = pymysql.connect(host="localhost", user="username", password="password", db="database_name")
  cursor = conn.cursor()

  # 准备查询
  sql = "SELECT * FROM table_name"

  # 执行查询
  cursor.execute(sql)

  # 检索数据
  data = cursor.fetchall()

  # 关闭连接
  cursor.close()
  conn.close()

  # 渲染模板
  return render_template('index.html', data=data)

if __name__ == "__main__":
  app.run(debug=True)</code>

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