PHP5.5基于mysqli连接MySQL数据库和读取数据操作实例详解

;extension=php_mysqli.dll

extension=php_mysqli.dll

<?php
  /* Connect to a MySQL server 连接数据库服务器 */
  $link = mysqli_connect(
        'localhost', /* The host to connect to 连接MySQL地址 */
        'user',   /* The user to connect as 连接MySQL用户名 */
        'password', /* The password to use 连接MySQL密码 */
        'world');  /* The default database to query 连接数据库名称*/
  if (!$link) {
    printf("Can't connect to MySQL Server. Errorcode: %s ", mysqli_connect_error());
    exit;
  }
  /* Send a query to the server 向服务器发送查询请求*/
  if ($result = mysqli_query($link, 'SELECT Name, Population FROM City ORDER BY Population DESC LIMIT 5')) {
    //print("Very large cities are: ");
    /* Fetch the results of the query 返回查询的结果 */
    while( $row = mysqli_fetch_assoc($result) ){
      printf("%s (%s) ", $row['Name'], $row['Population']);
    }
    /* Destroy the result set and free the memory used for it 结束查询释放内存 */
    mysqli_free_result($result);
  }
  /* Close the connection 关闭连接*/
  mysqli_close($link);
?>

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);
// Check connection
if ($conn->connect_error) {
  die("连接失败: " . $conn->connect_error);
}
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
  // 输出数据
  while($row = $result->fetch_assoc()) {
    echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
  }
} else {
  echo "0 结果";
}
$conn->close();
?>

<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);
// Check connection
if (!$conn) {
  die("连接失败: " . mysqli_connect_error());
}
$sql = "SELECT id, firstname, lastname FROM MyGuests";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
  // 输出数据
  while($row = mysqli_fetch_assoc($result)) {
    echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
  }
} else {
  echo "0 结果";
}
mysqli_close($conn);
?>

<?php
echo "<table style='border: solid 1px black;'>";
echo "<tr><th>Id</th><th>Firstname</th><th>Lastname</th></tr>";
class TableRows extends RecursiveIteratorIterator {
  function __construct($it) {
    parent::__construct($it, self::LEAVES_ONLY);
  }
  function current() {
    return "<td style='width:150px;border:1px solid black;'>" . parent::current(). "</td>";
  }
  function beginChildren() {
    echo "<tr>";
  }
  function endChildren() {
    echo "</tr>" . "n";
  }
}
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDBPDO";
try {
  $conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
  $conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
  $stmt = $conn->prepare("SELECT id, firstname, lastname FROM MyGuests");
  $stmt->execute();
  // 设置结果集为关联数组
  $result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
  foreach(new TableRows(new RecursiveArrayIterator($stmt->fetchAll())) as $k=>$v) {
    echo $v;
  }
}
catch(PDOException $e) {
  echo "Error: " . $e->getMessage();
}
$conn = null;
echo "</table>";
?>