Codeigniter: Different methods with different database connection (multiple database connection)

Question

I have some (model)methods and they connect separately to different databases.

I created two database configs from database.php, loaded them both in the model and created two methods; one connects to DB1, and other to DB2. (sample codes below)

When I replace $this->db by $DB1 or $DB2, I'm getting errors like:

Message: Undefined variable: DB1 // or DB2

Else, I get this error:

Message: Undefined property: Home::$db

I tried to include $DB= $this->load->database("database_name", TRUE); in each method to connect to a specific database. It works but I know its not a good practice connecting it again and again as I reuse the method.

I'm really confused.

Below are my codes:

database.php

$db['db1'] = array(
    'dsn'   => '',
    'hostname' => 'localhost',
    'username' => 'root',
    'password' => '',
    'database' => 'db1',
    'dbdriver' => 'mysqli',
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => (ENVIRONMENT !== 'production'),
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
);


$db['db2'] = array(
    'dsn'   => '',
    'hostname' => 'other_host',
    'username' => 'root',
    'password' => '',
    'database' => 'db2',
    'dbdriver' => 'mssql',
    'dbprefix' => '',
    'pconnect' => FALSE,
    'db_debug' => (ENVIRONMENT !== 'production'),
    'cache_on' => FALSE,
    'cachedir' => '',
    'char_set' => 'utf8',
    'dbcollat' => 'utf8_general_ci',
    'swap_pre' => '',
    'encrypt' => FALSE,
    'compress' => FALSE,
    'stricton' => FALSE,
    'failover' => array(),
    'save_queries' => TRUE
);

Model:

function __construct()
{
    parent::__construct();
    $DB1= $this->load->database("db1", TRUE);
    $DB2= $this->load->database("db2", TRUE);
}

public function get_from_db1($id)
{
    // $query = $this->db->get_where("my_table1",array("ID"=>$id));
    $query = $DB1->get_where("my_table1",array("ID"=>$id));
    return $query->row_array();
}


public function get_from_db2($id)
{
    // $query = $this->db->get_where("my_table2",array("ID"=>$id));
    $query = $DB2->get_where("my_table2",array("ID"=>$id));
    return $query->row_array();
}

Also:

• Do I declare and load my databases right?
• Where should I put the $this->load->database(); function, in the Controller or Model?

Please help!

Thanks in advance guys!

Answer 1

You need to define variable outside you constructor

public $DB1;
public $DB2;

And call it inside constructor as

function __construct()
{
parent::__construct();
$this->DB1= $this->load->database("db1", TRUE);
$this->DB2= $this->load->database("db2", TRUE);
}

And inside your function

public function get_from_db1($id)
{
// $query = $this->db->get_where("my_table1",array("ID"=>$id));
$query = $this->DB1->get_where("my_table1", array("ID" => $id));
return $query->row_array();
}


public function get_from_db2($id)
{
// $query = $this->db->get_where("my_table2",array("ID"=>$id));
$query = $this->DB2->get_where("my_table2", array("ID" => $id));
return $query->row_array();
}

Answer 2

did you load the main database class in the autoload.php:

$autoload['libraries'] = array('database');

you need this library to be loaded so that you can use the $db property.