连接到数据库
使用 MySQLi 进行连接：
<?php
$servername = "localhost";
$username = "username";
$password = "password";
$dbname = "database_name";
// 创建连接
$conn = new mysqli($servername, $username, $password, $dbname);
// 检查连接是否成功
if ($conn->connect_error) {
die("Connection failed: " . $conn->connect_error);
}
?>
查询数据
<?php
$sql = "SELECT column1, column2 FROM tablename";
$result = $conn->query($sql);
if ($result->num_rows > 0) {
// 输出每行数据
while($row = $result->fetch_assoc()) {
echo "Column1: " . $row["column1"]. " - Column2: " . $row["column2"]. "<br>";
}
} else {
echo "0 results";
}
// 关闭连接
$conn->close();
?>
插入数据
<?php
$sql = "INSERT INTO tablename (column1, column2) VALUES ('value1', 'value2')";
if ($conn->query($sql) === TRUE) {
echo "New record created successfully";
} else {
echo "Error: " . $sql . "<br>" . $conn->error;
}
// 关闭连接
$conn->close();
?>
更新数据
<?php
$sql = "UPDATE tablename SET column1 = 'new_value' WHERE condition";
if ($conn->query($sql) === TRUE) {
echo "Record updated successfully";
} else {
echo "Error updating record: " . $conn->error;
}
// 关闭连接
$conn->close();
?>
删除数据
<?php
$sql = "DELETE FROM tablename WHERE condition";
if ($conn->query($sql) === TRUE) {
echo "Record deleted successfully";
} else {
echo "Error deleting record: " . $conn->error;
}
// 关闭连接
$conn->close();
?>
在实际开发中，建议使用预处理语句以防止 SQL 注入攻击。下面是一个使用预处理语句的示例：
预处理语句
<?php
$sql = "INSERT INTO tablename (column1, column2) VALUES (?, ?)";
$stmt = $conn->prepare($sql);
$stmt->bind_param("ss", $value1, $value2);
// 设置参数并执行
$value1 = "new_value1";
$value2 = "new_value2";
$stmt->execute();
echo "New records created successfully";
// 关闭连接
$stmt->close();
$conn->close();
?>
以上是基于 MySQLi 扩展的示例。如果你更倾向于使用 PDO，代码结构会有一些差异，但基本原理是相似的。选择 MySQLi 还是 PDO 取决于你的个人偏好和项目需求。
转载请注明出处：http://www.zyzy.cn/article/detail/14080/MySQL