Codeigniter - Using Multiple Databases

问题:

database.php:

$db['default']['hostname'] = "192.168.2.104";
$db['default']['username'] = "webuser";
$db['default']['password'] = "----";
$db['default']['database'] = "vad";
$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['stats']['hostname'] = "192.168.2.104";
$db['stats']['username'] = "webuser";
$db['stats']['password'] = "---";
$db['stats']['database'] = "vad_stats";
$db['stats']['dbdriver'] = "mysql";
$db['stats']['dbprefix'] = "";
$db['stats']['pconnect'] = TRUE;
$db['stats']['db_debug'] = TRUE;
$db['stats']['cache_on'] = FALSE;
$db['stats']['cachedir'] = "";
$db['stats']['char_set'] = "utf8";
$db['stats']['dbcollat'] = "utf8_general_ci";

The issue is I can only define in the configuration one $active_group, default, or stats. I followed the CodeIgniter documentation and I added the following:

$DB2 = $this->load->database('stats', TRUE);

This way I connect to the second database, but I lose the connection to the first one. Does anyone have any ideas on how can I load the two database without having to do the following in all models constructors?

$database1 = $this->load->database('database1', TRUE);
$database2 = $this->load->database('database2', TRUE); 

Regards,

Pedro

回答1:

Instead of applying the hack as mentioned by Camacho you can also set the 'pconnect'-flag in the database.php file to FALSE for all connections.

回答2:

There is a bug in codeigniter. Inserting one line into a class will fix the whole thing. Here is the original source: http://koorb.wordpress.com/2007/11/16/codeigniter-connect-to-multiple-databases/

** This fix does not apply to PostgreSQL

Here is a copy just in case that site goes down.

The line number has changed. Here is the bug fix from codeigniter:

start bugfix

Description

all of the database calls go to the same database (last one initialized)

To fix the problem change the simple_query function in /system/database/DB_driver.php:

function simple_query($sql)
{
    if ( ! $this->conn_id)
    {
        $this->initialize();
    }

    $this->db_select(); //<-----------------  Added this line
    return $this->_execute($sql);
}

This completely fixes the problem, so you can do stuff like this in a model

$this->legacy_db = $this->load->database('legacy', true);

回答3:

currently, codeigniter cannot connect to multiple database in persisten connection. so, you should turn of the persisten of your connections. you may can do this..

$db['default']['pconnect'] = FALSE;

$db['stats']['pconnect'] = FALSE;

回答4:

I fix the problem changing the DB_driver.php on the framework.

In this function I add $this->db_select(); and you never lose your connection again when working with 2 databases.

function simple_query($sql)
{
    if ( ! $this->conn_id)
    {
        $this->initialize();
    }

    $this->db_select();

    return $this->_execute($sql);
}

回答5:

You may try modifying function CI_Session() in session.php file.

Replace

$this->CI->load->database();

with this

$this->CI->db1 = $this->CI->load->database('default', TRUE);
$this->CI->db2 = $this->CI->load->database('db2', TRUE);

In this way, you need not load 2 dbs in all the model files but shall use them directly using objects.

$this->db1 would be accessing default group db and $this->db2 would be accessing db2 group db. (both db groups should have been defined in database.php)

---

Sundar

回答6:

You don’t need to create separate database configurations if you only need to use a different database on the same connection. You can switch to a different database when you need to, like this:

$this->db->db_select($database2_name);

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