如何在PHP中获取MySQL表结构？加上所有表格的清单？

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";

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

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

// 查询所有表名
$tables = array();
$result = $conn->query("SHOW TABLES");
if ($result->num_rows > 0) {
  while($row = $result->fetch_assoc()) {
    $tables[] = $row["Tables_in_" . $dbname];
  }
}

// 查询每个表的结构
foreach ($tables as $table) {
  echo "表名：" . $table . "\n";
  $result = $conn->query("DESCRIBE " . $table);
  if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
      echo "字段名：" . $row["Field"] . "，类型：" . $row["Type"] . "，键：" . $row["Key"] . "\n";
    }
  }
  echo "\n";
}

$conn->close();
?>

$tables = array("table1", "table2", "table3");