mysql_select_db失败

Question

我正在使用 phpMyAdmin + MySQL。

我创建了一个数据库，现在正尝试在 PHP 脚本中建立连接。奇怪的是连接到数据库有效，所以我收到 "Connected to MySQL server" 消息，但是当我选择 'petfood' 数据库时，脚本显示 "DIED at selection".

知道为什么吗？谢谢，这是我的一段代码：

<?php

$user = 'localhost';
$pass = 'password';
$db_name = 'petfood';

$db_conn = new mysqli("localhost", $user, $pass, $db_name) or die("Cannot connect to DB");
echo "Connected to MySQL server";
mysql_select_db($db_name) or die("DIED at selection");
echo "Database Selected";

?>

Answer 1

找出不同之处：

$db_conn = new mysqli("localhost", $user, $pass, $db_name) or die("Cannot connect to DB");
                    ^----

mysql_select_db($db_name) or die("DIED at selection");
     ^---

如果你有适当的调试，你会被告知这个问题：

mysql_select_db($db_name) or die(mysql_error());
                                 ^^^^^^^^^^^^^^

当您可以让系统告诉您出了什么问题时，永远不要输出固定的（无用的）错误消息。

Answer 2

1: 使用 mysql

$dbhandle = mysql_connect($hostname, $username, $password) or die("Unable to connect to MySQL"); mysql_select_db("examples",$dbhandle) or die("Could not select examples"); $query = "SELECT name FROM mytable" ; $result = mysqli_query($query);

2: 使用 mysqli

$link = mysqli_connect("myhost","myuser","mypassw","mybd") or die("Error " . mysqli_error($link)); $query = "SELECT name FROM mytable" ; $result = mysqli_query($link, $query);

mysql_select_db失败

mysql_select_db failure

php

mysql

mysql-select-db