php增删改查实现流程

PHP 增删改查实现流程

数据库连接配置

创建 config.php 文件存放数据库连接信息：

<?php
$host = 'localhost';
$user = 'username';
$pass = 'password';
$dbname = 'database_name';

$conn = new mysqli($host, $user, $pass, $dbname);
if ($conn->connect_error) {
    die("Connection failed: " . $conn->connect_error);
}
?>

数据插入（Create）

通过表单提交数据并插入到数据库：

<?php
include 'config.php';

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $name = $_POST['name'];
    $email = $_POST['email'];

    $sql = "INSERT INTO users (name, email) VALUES ('$name', '$email')";
    if ($conn->query($sql) === TRUE) {
        echo "New record created successfully";
    } else {
        echo "Error: " . $sql . "<br>" . $conn->error;
    }
}
?>

<form method="post">
    Name: <input type="text" name="name"><br>
    Email: <input type="text" name="email"><br>
    <input type="submit">
</form>

数据查询（Read）

查询并显示数据库中的记录：

<?php
include 'config.php';

$sql = "SELECT id, name, email FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "ID: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"]. "<br>";
    }
} else {
    echo "0 results";
}
$conn->close();
?>

数据更新（Update）

更新数据库中的记录：

<?php
include 'config.php';

if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $id = $_POST['id'];
    $name = $_POST['name'];
    $email = $_POST['email'];

    $sql = "UPDATE users SET name='$name', email='$email' WHERE id=$id";
    if ($conn->query($sql) === TRUE) {
        echo "Record updated successfully";
    } else {
        echo "Error updating record: " . $conn->error;
    }
}

$sql = "SELECT id, name, email FROM users WHERE id=1";
$result = $conn->query($sql);
$row = $result->fetch_assoc();
?>

<form method="post">
    <input type="hidden" name="id" value="<?php echo $row['id']; ?>">
    Name: <input type="text" name="name" value="<?php echo $row['name']; ?>"><br>
    Email: <input type="text" name="email" value="<?php echo $row['email']; ?>"><br>
    <input type="submit" value="Update">
</form>

数据删除（Delete）

删除数据库中的记录：

<?php
include 'config.php';

if (isset($_GET['id'])) {
    $id = $_GET['id'];

    $sql = "DELETE FROM users WHERE id=$id";
    if ($conn->query($sql) === TRUE) {
        echo "Record deleted successfully";
    } else {
        echo "Error deleting record: " . $conn->error;
    }
}

$sql = "SELECT id, name, email FROM users";
$result = $conn->query($sql);

if ($result->num_rows > 0) {
    while($row = $result->fetch_assoc()) {
        echo "ID: " . $row["id"]. " - Name: " . $row["name"]. " - Email: " . $row["email"];
        echo " <a href='?id=".$row["id"]."'>Delete</a><br>";
    }
} else {
    echo "0 results";
}
$conn->close();
?>

安全注意事项

使用预处理语句防止SQL注入：

$stmt = $conn->prepare("INSERT INTO users (name, email) VALUES (?, ?)");
$stmt->bind_param("ss", $name, $email);
$stmt->execute();

完整示例结构

典型CRUD应用目录结构：

project/
├── config.php
├── create.php
├── read.php
├── update.php
└── delete.php