PHP中如何连接数据库
1，最简单的方式-mysql（面向过程）
<?php$con = mysql_connect("http://xtqh.zrghs.com","root","password");$select_db = mysql_select_db('test');if (!$select_db) { die("could not connect to the db:\n" . mysql_error());
}//查询代码$sql = "select * from db_table";$res = mysql_query($sql);if (!$res) { die("could get the res:\n" . mysql_error());
}while ($row = mysql_fetch_assoc($res)) { print_r($row);
}//查询代码
//关闭数据库连接mysql_close($con);?>
2，新的方式-mysqli（面向过程）
$mysql_server_name = 'localhost'; //改成自己的mysql数据库服务器$mysql_username = 'root'; //改成自己的mysql数据库用户名$mysql_password = 'password'; //改成自己的mysql数据库密码$mysql_database = 'test'; //改成自己的mysql数据库名$conn=mysqli_connect(http://cdxl.zrghs.com,$mysql_username,$mysql_password,$mysql_database); //连接数据库
//连接数据库错误提示if (mysqli_connect_errno($conn)) {
die("连接 MySQL 失败: " . mysqli_connect_error());
}mysqli_query($conn,"set names utf8"); //数据库编码格式
// mysqli_set_charset($conn,"utf8");//设置默认客户端字符集。
// mysqli_select_db($conn,$mysql_database); //更改连接的默认数据库
//查询代码$sql = “select * from db_table”;$query = mysqli_query($conn,$sql);while($row = mysqli_fetch_array($query)){ echo $row['title'];
}//查询代码
// 释放结果集+关闭MySQL数据库连接mysqli_free_result($result);mysqli_close($conn);
3，常用方式-mysqli（面向对象）
//连接数据库方式1$conn = new mysqli('localhost', 'root', 'password', 'test');//连接数据库方式2
// $conn = new mysqli();
// $conn -> connect('localhost', 'root', 'password', 'test');
//check connection (检查PHP是否连接上MYSQL)if ($conn -> connect_errno) { printf("Connect failed: %s\n", $conn->connect_error); exit();
}//查询代码$sql = “select * from db_table”;$query = $conn->query($sql);while($row = $query->fetch_array()){ echo $row['title'];
}//查询代码
//释放结果集+关闭MySQL连接$query1 -> free_result();$conn -> close();
4，PDO连接MySQL数据库
<?php$db = new PDO('mysql:http://sxyl.zrghs.com;dbname=test', 'root', 'password');try { foreach ($db->query('select * from db_table') as $row){ print_r($row);
} $db = null; //关闭数据库} catch (PDOException $e) { echo $e->getMessage();
}?>
5，ADODB连接MySQL数据库
<?php
//安装驱动-引入类即可
require_once './adodb5/adodb.inc.php';
$conn = &ADONewConnection('mysql');
$conn->connect('http://czdg.zrghs.com','root','password','test');
$conn->Execute("set names utf8");
//查询代码
$res = $conn->Execute("select * from db_table");
if (!$res){
echo $conn->ErrorMsg();
}else{
var_dump($res);
}
?>
//关闭连接
$conn->close();
6总结-关闭mysql数据库的连接方法
MySQL - 面向过程
mysql_close($conn);
MySQLi - 面向过程
mysqli_close($conn);
MySQLi - 面向对象
$conn->close();
PDO
$conn = null;
ADODB
$conn->close();
或
$conn->free();