php连接mysql公共文件、操作mysql数据库

//php连接mysql公共文件

<?php 
//数据库配置信息
$db_host = "localhost";//主机名
$db_user = "admin";//用户名
$db_pass = "admin";//密码
$db_name = "tablename";//数据库名
$charset = "utf8";//字符集

//php连接mysql服务器
if (!$link = @mysqli_connect($db_host, $db_user, $db_pass)) {
echo "<h2>数据库连接失败！</h2>";
die();
}
//选择数据库
if (!mysqli_select_db($link, $db_name)) {
echo "<h2>数据库选择失败！</h2>";
die();
}
//设置字符集对象
mysqli_set_charset($link, $charset);

 

//php执行mysql语句

//定义sql语句
$sql = "SELECT * FROM tablename";
//执行结果
//$link=mysqli_connect($db_host, $db_user, $db_pass)连接数据库成功后
$result = mysqli_query($link, $sql);
//结果导入到数组中
//MYSQLI_ASSOC为常量
$arrs = mysqli_fetch_all($result, MYSQLI_ASSOC) 
//获取记录数目
$records = mysqli_num_rows($result);

 mysqli_fetch_all

 

//mysql 查询数据

$sql = "SELECT * FROM photos WHERE username = '$username' ORDER BY id DESC LIMIT {$startrow}, {$pagesize}";

//mysql 更新数据

$sql = "UPDATE photos SET hits = {$hits} WHERE imgsrc = {$src}";