Multiple Database Connection

hai  to all,
   if possible to connect multiple database in codeigniter in hooks if this possible to do?

I have never had the need to use it but yes, you can:
Docs https://www.codeigniter.com/user_guide/d...-databases

I am pretty sure that this should apply to hooks to, but not if the hook point is before the db connection is made, for instance, 'pre-system' hook.
https://www.codeigniter.com/user_guide/g...ework-core

Not 100% on this, but thought that might help.

Paul.

I m using three DBs on my company projects. it is easy as 1,2,3. Configure it from database.php

I m using three DBs on my company projects.  it is easy as 1,2,3.  Configure it from database.php

In the User Guide it says:
Connecting to Multiple Databases
If you need to connect to more than one database simultaneously you can do so as follows:
$DB1 = $this->load->database('group_one', TRUE);
$DB2 = $this->load->database('group_two', TRUE);

Is this to be placed in each model?

Please enlighten me with a more detailed explanation!!

Thanks in advance,
HEKuiper

We do this by creating a connections file in the models folder (connections.php):

PHP Code:

class Connections extends CI_Model {

 var $db='';

 function __construct(){
 parent::__construct();
 }
 
 function _db_one() {

 $config['dbdriver'] = "mysqli";
 $config['dbprefix'] = "";
 $config['pconnect'] = FALSE;
 $config['db_debug'] = FALSE;
 $config['cache_on'] = FALSE;
 $config['cachedir'] = "";
 $config['char_set'] = "utf8";
 $config['dbcollat'] = "utf8_general_ci";
 $config['hostname'] = XXXXXXXXXXXXXXXXXXXX;
 $config['username'] = XXXXXXXXXXXXXXXXXXXX;
 $config['password'] = XXXXXXXXXXXXXXXXXXXX;
 $config['database'] = XXXXXXXXXXXXXXXXXXXX;

 $this->DB2=$this->load->database($config,TRUE);
 }

 function _db_two() {

 $config['dbdriver'] = "mysqli";
 $config['dbprefix'] = "";
 $config['pconnect'] = FALSE;
 $config['db_debug'] = FALSE;
 $config['cache_on'] = FALSE;
 $config['cachedir'] = "";
 $config['char_set'] = "utf8";
 $config['dbcollat'] = "utf8_general_ci";
 $config['hostname'] = XXXXXXXXXXXXXXXXXXXX;
 $config['username'] = XXXXXXXXXXXXXXXXXXXX;
 $config['password'] = XXXXXXXXXXXXXXXXXXXX;
 $config['database'] = XXXXXXXXXXXXXXXXXXXX;

 $this->DB2=$this->load->database($config,TRUE);
 }

} 


Then in our models, we have:

PHP Code:

class Orders extends Connections {

 function __construct() {
   // Call the Model constructor
   parent::__construct();
   $this->_db_one();
 }
public function adjust_cart($cart_key, $productid, $qty) {
    $this->DB2->where('sessionid', $cart_key); 
    $this->DB2->where('productid', $productid); 
    $this->DB2->update($this->tbl_order_storage, array('qty'=>$qty, 'date'=>time()));   
  } 


In the User Guide it says:
Connecting to Multiple Databases
If you need to connect to more than one database simultaneously you can do so as follows:
$DB1 = $this->load->database('group_one', TRUE);
$DB2 = $this->load->database('group_two', TRUE);

Is this to be placed in each model?

Please enlighten me with a more detailed explanation!!

Thanks in advance,
HEKuiper

It can be done in a number of different ways. The main thing to understand is that the var set by the return from $this->load->database('some_group', TRUE) has to be visible (in scope) in the model that uses it.

In other words, using this statement

PHP Code:

$DB2 = $this->load->database('db_config2', TRUE); 


The var $DB2 needs to be in scope to the model that uses it.

You could make $DB2 a public property of a Controller.

PHP Code:

Class Welcome extends CI_Controller
{
    public $DB2;

    function __construct()
    {
        parent::__construct();
        $this->DB2 = $this->load->database('db_config2', true);
        $this->load->model('othermodel');
    }

    public function index()
    {
        echo $this->othermodel->get_event();
    } 


And then use DB2 in "othermodel"

PHP Code:

class Othermodel extends CI_Model
{
   public function get_event()
   {

       return $this->DB2
           ->query("Select eventtitle from events where eventid = 20")
           ->row()
           ->eventtitle;
   }
} 


$this->DB2 could be used in any number of other models the controller requires. I don't intend to promote this approach as optimal or even truly desirable. Arguments against this approach are easily raised. Rather, the intent is only to demonstrate another way to make a connection visible to multiple models.  

Ultimately "where" you load additional databases probably depends more on how often you need more than one. That said, @Kaosweaver's answer is a great example of how easily create multiple connections in an arbitrary number of model classes.

In the User Guide it says:
Connecting to Multiple Databases
If you need to connect to more than one database simultaneously you can do so as follows:
$DB1 = $this->load->database('group_one', TRUE);
$DB2 = $this->load->database('group_two', TRUE);

Is this to be placed in each model?

Please enlighten me with a more detailed explanation!!

Thanks in advance,
HEKuiper

It can be done in a number of different ways. The main thing to understand is that the var set by the return from $this->load->database('some_group', TRUE) has to be visible (in scope) in the model that uses it.

In other words, using this statement

PHP Code:

$DB2 = $this->load->database('db_config2', TRUE); 


The var $DB2 needs to be in scope to the model that uses it.

You could make $DB2 a public property of a Controller.

PHP Code:

Class Welcome extends CI_Controller
{
    public $DB2;

    function __construct()
    {
        parent::__construct();
        $this->DB2 = $this->load->database('db_config2', true);
        $this->load->model('othermodel');
    }

    public function index()
    {
        echo $this->othermodel->get_event();
    } 


And then use DB2 in "othermodel"

PHP Code:

class Othermodel extends CI_Model
{
   public function get_event()
   {

       return $this->DB2
           ->query("Select eventtitle from events where eventid = 20")
           ->row()
           ->eventtitle;
   }
} 


$this->DB2 could be used in any number of other models the controller requires. I don't intend to promote this approach as optimal or even truly desirable. Arguments against this approach are easily raised. Rather, the intent is only to demonstrate another way to make a connection visible to multiple models.  

Ultimately "where" you load additional databases probably depends more on how often you need more than one. That said, @Kaosweaver's answer is a great example of how easily create multiple connections in an arbitrary number of model classes.

Wow this is way less code!!  Thanks.

I have 3 websites and 4 databases - the 4th one I want to share commonalities with all 3 websites. 

Example: create 1 blog post and display it on 3 websites...  Taking DRY to a whole new level!!  :-)

Again, Thanks!!
HEKuiper

You can create a MY_Model and place all the code you use all the time in it,
then extend all your Models from the MY_Model.

What did you Try? What did you Get? What did you Expect?

Joined CodeIgniter Community 2009.  ( Skype: insitfx )