Mysqli 简明教程
MySQLi - Connection
MySQL Connection Using MySQL Binary
你可以在命令提示符下使用 mysql 二进制文件建立 MySQL 数据库。
You can establish the MySQL database using the mysql binary at the command prompt.
Example
下面是一个从命令提示符连接到 MySQL 服务器的简单示例 −
Here is a simple example to connect to the MySQL server from the command prompt −
[root@host]# mysql -u root -p
Enter password:******
这会给你 MySQL 命令提示符,你可以在其中执行任何 SQL 命令。以下是上述命令的结果−
This will give you the mysqli command prompt where you will be able to execute any SQL command. Following is the result of above command −
以下代码块显示了以上代码的结果 −
The following code block shows the result of above code −
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 2854760 to server version: 5.0.9
Type 'help;' or '\h' for help. Type '\c' to clear the buffer.
在上述示例中,我们使用了 root 作为用户,但你也可以使用任何其他用户。任何用户都可以执行所有被允许执行的 SQL 操作。
In the above example, we have used root as a user but you can use any other user as well. Any user will be able to perform all the SQL operations, which are allowed to that user.
你可以随时使用 mysql> 提示符下的 exit 命令断开 MySQL 数据库连接。
You can disconnect from the MySQL database any time using the exit command at mysql> prompt.
mysql> exit
Bye
MySQL Connection Using PHP Script
PHP 提供 mysqli 构造或 mysqli_connect() 函数来打开一个数据库连接。此函数采用六个参数,并且在成功时返回一个 MySQL 链接标识符,在失败时返回 FALSE。
PHP provides mysqli contruct or mysqli_connect() function to open a database connection. This function takes six parameters and returns a MySQL link identifier on success or FALSE on failure.
Syntax
$mysqli = new mysqli($host, $username, $passwd, $dbName, $port, $socket);
Sr.No. |
Parameter & Description |
1 |
$host Optional − The host name running the database server. If not specified, then the default value will be localhost:3306. |
2 |
$username Optional − The username accessing the database. If not specified, then the default will be the name of the user that owns the server process. |
3 |
$passwd Optional − The password of the user accessing the database. If not specified, then the default will be an empty password. |
4 |
$dbName Optional − database name on which query is to be performed. |
5 |
$port Optional − the port number to attempt to connect to the MySQL server.. |
6 |
$socket Optional − socket or named pipe that should be used. |
你可以随时使用另一个 PHP 函数 close() 来断开 MySQL 数据库连接。
You can disconnect from the MySQL database anytime using another PHP function close().
Example
尝试以下示例以连接到 MySQL 服务器 −
Try the following example to connect to a MySQL server −
将以下示例复制粘贴为 mysql_example.php:
Copy and paste the following example as mysql_example.php −
<html>
<head>
<title>Connecting MySQL Server</title>
</head>
<body>
<?php
$dbhost = 'localhost';
$dbuser = 'root';
$dbpass = 'root@123';
$mysqli = new mysqli($dbhost, $dbuser, $dbpass);
if($mysqli→connect_errno ) {
printf("Connect failed: %s<br />", $mysqli→connect_error);
exit();
}
printf('Connected successfully.<br />');
$mysqli→close();
?>
</body>
</html>