与Mysqli相关的四种数据库取值

<!--取值方案一：通过数字数组 fetch_row()-->
<meta http-equiv="Content-Type" content="text/html" charset="utf-8">
<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2015/8/27
 * Time: 11:00
 */

//数据库连接
$_mysqli=new mysqli('localhost','root','******','testguest');

//设置编码
$_mysqli->set_charset('utf8');

//创建SQL语句
$_sql="SELECT * FROM tg_user";

//执行SQL语句，并将结果集赋值给$_result
$_result=$_mysqli->query($_sql);

//索引数组(第一行的信息)
$_row=$_result->fetch_row();
echo $_row[3];

//索引整个表的信息
while(!!$_row=$_result->fetch_row()){
    echo $_row[3].'<br/>';
}

//销毁结果集
$_result->free();

//数据库断开
$_mysqli->close();

?> 

<!--取值方案二：通过关联数组 fetch_assoc()-->
<meta http-equiv="Content-Type" content="text/html" charset="utf-8">
<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2015/8/27
 * Time: 11:18
 */
//数据库连接
$_mysqli=new mysqli('localhost','root','******','testguest');

//设置编码
$_mysqli->set_charset('utf8');

//创建SQL语句
$_sql="SELECT * FROM tg_user";

//执行SQL语句，并将结果集赋值给$_result
$_result=$_mysqli->query($_sql);

//索引数组(第一行的信息)
$_assoc=$_result->fetch_assoc();
echo $_assoc['tg_username'].'<br/><br/>';

//索引整个表的信息
while(!!$_assoc=$_result->fetch_assoc()){
    echo $_assoc['tg_username'].'<br/>';
}

//销毁结果集
$_result->free();

//数据库断开
$_mysqli->close();
?> 

<!--取值方案三：通过 关联+数字数组 fetch_array()-->
<meta http-equiv="Content-Type" content="text/html" charset="utf-8">
<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2015/8/27
 * Time: 11:39
 */
$_mysqli=new mysqli('localhost','root','******','testguest');

if(mysqli_connect_errno()){
    echo '数据库连接错误，错误信息：'.mysqli_connect_error();
    exit();
}

//设置编码
$_mysqli->set_charset('utf8');

$_sql='SELECT * FROM tg_user';

$_result=$_mysqli->query($_sql);

//打印第一条信息
//print_r($_result);
$_array=$_result->fetch_array();
echo $_array[3].'<br/>';
echo $_array['tg_username'].'<br/>';

//遍历
while(!!$_array=$_result->fetch_array()){
    echo $_array[3].'<br/>';
    echo $_array['tg_username'].'<br/>';
}

$_result->free();
$_mysqli->close();
?> 

<!--取值方案四：通过面向对象（OOP） fetch_object()-->
<meta http-equiv="Content-Type" content="text/html" charset="UTF-8">
<?php
/**
 * Created by PhpStorm.
 * User: Administrator
 * Date: 2015/8/27
 * Time: 11:54
 */
$_mysqli=new mysqli('localhost','root','******','testguest');

if(mysqli_connect_errno()){
    echo '数据库连接错误，错误信息是：'.mysqli_connect_error();
    exit();
}

//设置数据库编码
$_mysqli->set_charset('utf8');

$_sql='SELECT * FROM tg_user';

$_result=$_mysqli->query($_sql);

$_object=$_result->fetch_object();
echo $_object->tg_username.'<br/>';

//遍历
while(!!$_object=$_result->fetch_object()){
    echo $_object->tg_username.'<br/>';
}

$_result->free();
$_mysqli->close();
?>