PHP与MySQL是经典的Web开发组合,掌握它们之间的连接方式是PHP开发的基础技能。以下是PHP连接MySQL数据库的核心知识点:
<?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);
}
echo "连接成功";
?>
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "myDB";
try {
$conn = new PDO("mysql:host=$servername;dbname=$dbname", $username, $password);
// 设置 PDO 错误模式为异常
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
echo "连接成功";
}
catch(PDOException $e) {
echo "连接失败: " . $e->getMessage();
}
?>
$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";
}
$stmt = $conn->prepare("SELECT id, firstname, lastname FROM MyGuests");
$stmt->execute();
// 设置结果集为关联数组
$result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
foreach($stmt->fetchAll() as $k=>$v) {
echo "id: " . $v["id"]. " - Name: " . $v["firstname"]. " " . $v["lastname"]. "<br>";
}
$sql = "INSERT INTO MyGuests (firstname, lastname, email)
VALUES ('John', 'Doe', 'john@example.com')";
if ($conn->query($sql) === TRUE) {
echo "新记录插入成功";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
$stmt = $conn->prepare("INSERT INTO MyGuests (firstname, lastname, email)
VALUES (:firstname, :lastname, :email)");
$stmt->bindParam(':firstname', $firstname);
$stmt->bindParam(':lastname', $lastname);
$stmt->bindParam(':email', $email);
// 插入行
$firstname = "John";
$lastname = "Doe";
$email = "john@example.com";
$stmt->execute();
echo "新记录插入成功";
// MySQLi
$conn->close();
// PDO
$conn = null;
password_hash()
对于新项目,建议使用PDO,因为它更加灵活和安全。
// MySQLi错误处理
if (!$conn->query($sql)) {
printf("Error: %s\n", $conn->error);
}
// PDO错误处理
$conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
掌握这些基础知识后,您就可以开始在PHP应用中与MySQL数据库进行交互了。