【问题标题】:Codeigniter dynamic database connectionCodeigniter 动态数据库连接
【发布时间】:2013-10-09 04:09:55
【问题描述】:

我是 php/OOP 的初学者,有一个关于动态更改我的数据库连接的问题。

这是我的 main.php 的样子:

<?php  if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Main extends CI_Controller {


function __construct()
{

    parent::__construct();

    /* Standard Libraries of codeigniter are required */
    $this->load->database($connectdb);
    $this->load->helper('url');
    $this->load->library('grocery_CRUD');
}

public function index()
{


            if ($_POST["username"] == "root")
                    {
                            $connectdb="default";
                    }


                    if ($_POST["username"] == "user1")
                    {
                            $connectdb="default1";
                    }

            if ($_POST["username"] == "user2")
                    {
                            $connectdb="default2";
                    }


    $connect = @mysql_connect("localhost", $_POST["username"], $_POST["password"]);//won't display the warning if any.
    if (!$connect)
    {
            echo 'Server error. Please try again sometime. CON';
    }else{
            print("<a href=\"http://v-admindb/ci/index.php/main/employees?username=".$_POST["username"]."\">Employees</a>");
            echo "<br>";
            print("<a href=\"http://v-admindb/ci/index.php/main/visitors?username=".$_POST["username"]."\">Visitors</a>");
    }//Just an example to ensure that we get into the function
// LOAD LIBRARIES
}

public function employees()
{
    $this->grocery_crud->set_table('employees');
    $output = $this->grocery_crud->render();
    $this->_example_output($output);
}

public function visitors()
{
    $this->grocery_crud->set_table('visitors');
    $output = $this->grocery_crud->render();
    $this->_example_output($output);
}


function _example_output($output = null)

{
    $this->load->view('our_template.php',$output);
}
}

这是我的database.php:

$db['default']['hostname'] = 'localhost';
$db['default']['username'] = 'root';
$db['default']['password'] = 'root';
$db['default']['database'] = 'my_new_cms';
$db['default']['dbdriver'] = 'mysql';
$db['default']['dbprefix'] = '';
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = TRUE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = '';
$db['default']['char_set'] = 'utf8';
$db['default']['dbcollat'] = 'utf8_general_ci';
$db['default']['swap_pre'] = '';
$db['default']['autoinit'] = TRUE;
$db['default']['stricton'] = FALSE;


//CONNECTION FOR user1
$db['default1']['hostname'] = 'localhost';
$db['default1']['username'] = 'user1';
$db['default1']['password'] = 'user1';
$db['default1']['database'] = 'my_new_cms';
$db['default1']['dbdriver'] = 'mysql';
$db['default1']['dbprefix'] = '';
$db['default1']['pconnect'] = TRUE;
$db['default1']['db_debug'] = TRUE;
$db['default1']['cache_on'] = FALSE;
$db['default1']['cachedir'] = '';
$db['default1']['char_set'] = 'utf8';
$db['default1']['dbcollat'] = 'utf8_general_ci';
$db['default1']['swap_pre'] = '';
$db['default1']['autoinit'] = TRUE;
$db['default1']['stricton'] = FALSE;


//CONNECTION FOR user2
$db['default2']['hostname'] = 'localhost';
$db['default2']['username'] = 'user2';
$db['default2']['password'] = 'user2';
$db['default2']['database'] = 'my_new_cms';
$db['default2']['dbdriver'] = 'mysql';
$db['default2']['dbprefix'] = '';
$db['default2']['pconnect'] = TRUE;
$db['default2']['db_debug'] = TRUE;
$db['default2']['cache_on'] = FALSE;
$db['default2']['cachedir'] = '';
$db['default2']['char_set'] = 'utf8';
$db['default2']['dbcollat'] = 'utf8_general_ci';
$db['default2']['swap_pre'] = '';
$db['default2']['autoinit'] = TRUE;
$db['default2']['stricton'] = FALSE;

当我尝试登录时,我会出现这个错误:

遇到了 PHP 错误

严重性:通知

消息:未定义变量:connectdb

文件名:controllers/main.php

行号:12 遇到错误

您尚未选择要连接的数据库类型。

将$this-&gt;load-&gt;database($connectdb) 更改为default、default1 或default2 使其工作。如何在其中放置一个变量,以便连接参数根据谁登录而改变?

希望有人能帮忙,谢谢! 埃里克

【问题讨论】:

  • 如果您要使用 codeigniter,请先阅读一些手册 ...

标签: php mysql database codeigniter dynamic


【解决方案1】:

您应该在application/config/database.php´中提供所有数据库信息

通常,您会设置默认数据库组,如下所示:

$db['default']['hostname'] = "localhost";
$db['default']['username'] = "root";
$db['default']['password'] = "";
$db['default']['database'] = "database_name";
$db['default']['dbdriver'] = "mysql";
$db['default']['dbprefix'] = "";
$db['default']['pconnect'] = TRUE;
$db['default']['db_debug'] = FALSE;
$db['default']['cache_on'] = FALSE;
$db['default']['cachedir'] = "";
$db['default']['char_set'] = "utf8";
$db['default']['dbcollat'] = "utf8_general_ci";
$db['default']['swap_pre'] = "";
$db['default']['autoinit'] = TRUE;
$db['default']['stricton'] = FALSE;

请注意,登录信息和设置在名为 $db['default'] 的数组中提供。

然后您可以在新数组中添加另一个数据库 - 我们称之为“anotherdb”。

$db['anotherdb']['hostname'] = "localhost";
$db['anotherdb']['username'] = "root";
$db['anotherdb']['password'] = "";
$db['anotherdb']['database'] = "another_database_name";
$db['anotherdb']['dbdriver'] = "mysql";
$db['anotherdb']['dbprefix'] = "";
$db['anotherdb']['pconnect'] = TRUE;
$db['anotherdb']['db_debug'] = FALSE;
$db['anotherdb']['cache_on'] = FALSE;
$db['anotherdb']['cachedir'] = "";
$db['anotherdb']['char_set'] = "utf8";
$db['anotherdb']['dbcollat'] = "utf8_general_ci";
$db['anotherdb']['swap_pre'] = "";
$db['anotherdb']['autoinit'] = TRUE;
$db['anotherdb']['stricton'] = FALSE;

现在如果你想使用第二个数据库,去吧

$DB_another = $this->load->database('anotherdb', TRUE); 

然后,你将不是 $this-&gt;db-&gt;foo() ,而是 $DB_another-&gt;foo()

您可以将其扩展到多个这样的组

 $DB2 = $this->load->database('anotherdb1', TRUE); 
 $DB3 = $this->load->database('anotherdb2', TRUE); 

详情请看这里: http://ellislab.com/codeigniter/user-guide/database/connecting.html

【讨论】:

  • 我只有一个数据库多表。您上面的内容似乎仅适用于不同的数据库。有没有办法动态改变main.php中的数据库连接?
【解决方案2】:
$this->load->database($connectdb);

问题就在这里,你在索引函数中设置的构造函数中加载了这个变量。

__constructor() 在 index() 之前被触发 所以我想你应该这样做:

class Main extends CI_Controller {
private $connectdb;

function __construct()
{

    parent::__construct();

    /* Standard Libraries of codeigniter are required */
    $this->_setConnectdb();
    $this->load->database($this->connectdb);
    $this->load->helper('url');
    $this->load->library('grocery_CRUD');
}

public function _setConnectdb()
{
if ( $_POST["username"] == "root" ) {
    $this->connectdb = "default";
}

if ( $_POST["username"] == "user1" ) {
    $this->connectdb = "default1";
}

if ( $_POST["username"] == "user2" ) {
    $this->connectdb = "default2";
}

【讨论】:

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