Connecting multiple database in codeigniter

Rakesh Sharma      8 Comments  

How to connecting multiple database in codeigniter :-

Sometimes we need to use two or multiple database for a single site. If you need to connect to more than one database simultaneously. codeigniter provide an easy handy feature to connect multiple database. for this we need to add some config of databases and load the db instance. we need to set only PCONNECT(persistent connection) to set TRUE/FALSE. Below we will see how to connect multiple databse in codeigniter with direct loading db object in controller/model and how to connect multiple database in codeigniter using library.

1. set your database configuration :- go to “application/config/database.php” and add below code (add your db settings)

$db['default']['hostname'] = 'localhost';
$db['default']['username'] = 'root';
$db['default']['password'] = '';
$db['default']['database'] = 'test1';
$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;

//Another database connection.

$db['db2']['hostname'] = 'localhost';
$db['db2']['username'] = 'root';
$db['db2']['password'] = '';
$db['db2']['database'] = 'test2';
$db['db2']['dbdriver'] = 'mysql';
$db['db2']['dbprefix'] = '';
$db['db2']['pconnect'] = FALSE;
$db['db2']['db_debug'] = TRUE;
$db['db2']['cache_on'] = FALSE;
$db['db2']['cachedir'] = '';
$db['db2']['char_set'] = 'utf8';
$db['db2']['dbcollat'] = 'utf8_general_ci';
$db['db2']['swap_pre'] = '';
$db['db2']['autoinit'] = TRUE;
$db['db2']['stricton'] = FALSE;

2. Use in controller/model :-

Using direct load db instance :- after set configuration we need to only load and use database objects.

// Running first db query.
$qry = $this->db->query("SELECT * FROM users ORDER BY `u_id` DESC");

// Loading second db and running query.
$CI = &get_instance();
//setting the second parameter to TRUE (Boolean) the function will return the database object.
$this->db2 = $CI->load->database('db2', TRUE);
$qry = $this->db2->query("SELECT * FROM cds");

Using library :- create a library file in “application/libraries/multipledb.php” (change file name as you want)

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed'); 
class Multipledb {
  var $db = NULL;
  function __construct(){
    $CI = &get_instance();
    $this->db = $CI->load->database('db2', TRUE);	
  // Add more functions two use commonly.
  public function save(){

Use library in controller/model/view :-

$this->load->library('multipledb'); // loading library.
$query2 = $this->multipledb->db->query('your query goes here'); // running query using library.
$this->multipledb->save();// calling library function.

Now you have all set to connecting two or multiple databases in codeigniter.

  • Damian

    It works good for me. Thanks.

  • iceberg

    Hey thanks for your tutorial, so i have a question, i have a login page, but i need to add a database combobox, so the user can choose the database where the user will work, i mean for example: Choose database:BD1 or DB2 User:XXXX Password:XXXX, so can you give some ideas how to achieve that? Thank you.

    • iceberg

      Hi again i got it, it works , Thanks.

      • rakesh sharma

        Glad to know it’s helpful for you, Thanks

      • Algie

        Hi, how have you done this?

  • Raúl Narvaez

    Good contribution, my question is:
    As I connect to a database manually if you use the mysqli driver?

  • anjali

    thanks alot as a fresher without asking elseone, i did it to make others proud of me..

  • Mia Torres

    hey, Do you know how to poll fast a data using this ?