问题
I did search for a solution, but found nothing helpfull. This question was about using multiple databases with datamapper but I already use that method.
user model:
class User extends DataMapper {
var $prefix = "app_";
var $db_params = 'default';
...
company model:
class Company extends DataMapper {
var $prefix = "tbl_";
var $db_params = 'super';
...
I have the above models. They are related as user-has-one-company and company-has-many-user. When I create a company, a user will be created automatically and the relationship is made with succes.
However, when I try to delete a company, or try to acces the related company of a user. DataMapper looks for the user table in the wrong place.
I got the following error:
A Database Error Occurred
Error Number: 1146
Table 'a1210alf.app_users' doesn't exist
SELECT `tbl_companies`.* FROM (`tbl_companies`) LEFT OUTER JOIN `app_users` app_users ON `tbl_companies`.`id` = `app_users`.`company_id` WHERE `app_users`.`id` = 4
In my CI config I have two different settings for two databases 'default' and 'super'. And I set the correct one in the model. The table app_users does exist, all fields needed are there. Not sure what I am doing wrong.
回答1:
I'm using this solution for a while now. It still didn't 'broke' in any case .. so I guess it's the correct way to do it.
First I created a 'BaseModel' which extends 'DataMapper'. The constructor looks like this:
/**
* Constructor: calls parent constructor
*/
function __construct($id = NULL, $db = NULL)
{
if ($db != NULL && $this->db_params == '') {
// use these params as default
$this->db_params = array_merge(array(
'dbdriver' => 'mysql',
'pconnect' => true,
'db_debug' => true,
'cache_on' => false,
'char_set' => 'utf8',
'cachedir' => '',
'dbcollat' => 'utf8_general_ci',
'autoinit' => true,
'stricton' => false,
), $db);
}
elseif($this->db_params == '') {
$CI =& get_instance();
$cid = $CI->session->userdata('cid');
if($cid != false || $cid != '') {
$userDB = new Database();
$userDB->get_where(array('company_id'=>$cid));
if($userDB->exists()) {
$this->db_params = array(
'hostname' => $userDB->dbhost,
'database' => $userDB->dbname,
'username' => $userDB->dbuser,
'password' => $userDB->dbpass,
'dbdriver' => 'mysql',
'pconnect' => true,
'db_debug' => true,
'cache_on' => false,
'char_set' => 'utf8',
'cachedir' => '',
'dbcollat' => 'utf8_general_ci',
'autoinit' => true,
'stricton' => false,
);
}
}
}
parent::__construct($id);
}
Now if you create an instance of a user we should do $u = new User(NULL, $this->udb);
where $this->udb
are the connection params which are loaded in the main controller.
This way the model will get the correct params each time. AND if a related object is needed the BaseModel knows where to get the correct params.
All I care about is that it works :p
NOTE: there is no need to set var $db_params = 'default';
in each model. If you do, it will overwrite the params you set in the constructor of BaseModel.
Maybe this will be usefull to someone. But this was a special case and I don't encourage anyone to design their database this way if you are using CodeIgniter + Datamapper.
回答2:
I think you can't resolve relations over different databases. You have to emulate this with your own logic.
来源:https://stackoverflow.com/questions/16171576/joining-tables-in-different-databases-with-the-ci-datamapper-orm