Php Mysql 简明教程

PHP & MySQL - Select Database Example

PHP 使用 mysqli_select_db 函数来选择要执行查询的数据库。此函数接受两个参数,并成功时返回 TRUE,失败时返回 FALSE。

PHP uses mysqli_select_db function to select the database on which queries are to be performed. This function takes two parameters and returns TRUE on success or FALSE on failure.

Syntax

mysqli_select_db ( mysqli $link , string $dbname ) : bool

Sr.No.

Parameter & Description

1

$link Required - A link identifier returned by mysqli_connect() or mysqli_init().

2

$dbname Required - Name of the database to be connected.

Example

尝试以下示例以选择数据库 −

Try the following example to select a database −

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>Selecting MySQL Database</title>
   </head>
   <body>
      <?php
         $dbhost = 'localhost';
         $dbuser = 'root';
         $dbpass = 'root@123';
         $conn = mysqli_connect($dbhost, $dbuser, $dbpass);

         if(! $conn ) {
            die('Could not connect: ' . mysqli_error($conn));
         }
         echo 'Connected successfully<br />';
         $retval = mysqli_select_db( $conn, 'TUTORIALS' );

         if(! $retval ) {
            die('Could not select database: ' . mysqli_error($conn));
         }
         echo "Database TUTORIALS selected successfully\n";
         mysqli_close($conn);
      ?>
   </body>
</html>

Output

访问部署在 Apache Web 服务器上的 mysql_example.php, 并验证输出。

Access the mysql_example.php deployed on apache web server and verify the output.

Database TUTORIALS selected successfully