php数据库增删改查代码
时间: 2023-09-16 21:06:30 浏览: 39
以下是一个使用 PHP 连接 MySQL 数据库并进行增删改查操作的范例代码:
连接到数据库:
```php
<?php
$servername = "localhost"; // 服务器名称
$username = "username"; // 用户名
$password = "password"; // 密码
$dbname = "database_name"; // 数据库名称
// 创建连接
$conn = mysqli_connect($servername, $username, $password, $dbname);
// 检查连接是否成功
if (!$conn) {
die("Connection failed: " . mysqli_connect_error());
}
?>
```
插入数据:
```php
<?php
$sql = "INSERT INTO mytable (firstname, lastname, email) VALUES ('John', 'Doe', 'john@example.com')";
if (mysqli_query($conn, $sql)) {
echo "Record inserted successfully";
} else {
echo "Error inserting record: " . mysqli_error($conn);
}
?>
```
更新数据:
```php
<?php
$sql = "UPDATE mytable SET lastname='Doe Jr.' WHERE id=1";
if (mysqli_query($conn, $sql)) {
echo "Record updated successfully";
} else {
echo "Error updating record: " . mysqli_error($conn);
}
?>
```
删除数据:
```php
<?php
$sql = "DELETE FROM mytable WHERE id=1";
if (mysqli_query($conn, $sql)) {
echo "Record deleted successfully";
} else {
echo "Error deleting record: " . mysqli_error($conn);
}
?>
```
查询数据:
```php
<?php
$sql = "SELECT id, firstname, lastname FROM mytable";
$result = mysqli_query($conn, $sql);
if (mysqli_num_rows($result) > 0) {
while($row = mysqli_fetch_assoc($result)) {
echo "id: " . $row["id"]. " - Name: " . $row["firstname"]. " " . $row["lastname"]. "<br>";
}
} else {
echo "0 results";
}
?>
```
注意:以上代码仅仅是一个简单的范例,实际应用中需要注意 SQL 注入问题并且使用预处理语句来避免。