Error in overrideing the function getDbConnection() to use 2 databases

hdbgdz · August 19, 2010, 5:16pm

Hi,

I’m trying to write a program to take data from one database, manipulate the data, and then place it into a different database. All while using the Yii framework.

In the /config/main.php file I have added a second database like such:

            'db'=&gt;array(


                    'class'=&gt;'CDbConnection',


                    'connectionString' =&gt; 'mysql:host=****;dbname=****',


                    'emulatePrepare' =&gt; true,


                    'username' =&gt; '***',


                    'password' =&gt; '***',


                    'charset' =&gt; 'utf8',


            ),





            'db2'=&gt;array(


                    'class' =&gt; 'CDBConnection',


                    'connectionString' =&gt; 'mysql:host=****;dbname=****',


                    'emulatePrepare' =&gt; true,


                    'username' =&gt; '***',


                    'password' =&gt; '***',


                    'charset' =&gt; 'utf8',


            ),

Then in the /components directory I created a file called AltActiveRecord.php which extends CActiveRecord and overrides the function getDbConnection like such:

<?php

    abstract class AltActiveRecord extends CActiveRecord


    {


            public function getDbConnection()





            {





                    if(self::&#036;db&#33;==null)





                            return self::&#036;db;





                    else





                    {





                            self::&#036;db=Yii::app()-&gt;db2;





                            if(self::&#036;db instanceof CDbConnection)





                            {





                                    self::&#036;db-&gt;setActive(true);





                                    return self::&#036;db;





                            }





                            else





                                    throw new CDbException(Yii::t('yii','Active Record requires a &quot;db&quot; CDbConnection application component.'));





                    }





            }


    }

?>

In the model that I want to use db2 I have it extend AltActiveRecord instead of CActiveRecord. However when I try to go to the page I get an error.

Error 500

include(CDBConnection.php): failed to open stream: No such file or directory

With a stack dump of:

include(CDBConnection.php): failed to open stream: No such file or

directory (/Raid/www/restricted/code_store/yii_fw/1.1.3/YiiBase.php:338)

Stack trace:

#0 /Raid/www/restricted/code_store/yii_fw/1.1.3/YiiBase.php(184): import()

#1 /Raid/www/restricted/code_store/yii_fw/1.1.3/base/CModule.php(362):

createComponent()

#2 /Raid/www/restricted/code_store/yii_fw/1.1.3/base/CModule.php(86):

CWebApplication->getComponent()

#3

/Raid/www/restricted/www/sdms/DM/johnyii/protected/components/AltActiveRecord.php(16):

CWebApplication->__get()

#4

/Raid/www/restricted/code_store/yii_fw/1.1.3/db/ar/CActiveRecord.php(2048):

data_products->getDbConnection()

#5

/Raid/www/restricted/code_store/yii_fw/1.1.3/db/ar/CActiveRecord.php(353):

CActiveRecordMetaData->__construct()

#6

/Raid/www/restricted/www/sdms/DM/johnyii/protected/models/data_products.php(21):

model()

#7

/Raid/www/restricted/www/sdms/DM/johnyii/protected/controllers/SiteController.php(44):

model()

#8

/Raid/www/restricted/code_store/yii_fw/1.1.3/web/actions/CInlineAction.php(32):

SiteController->actionIndex()

#9 /Raid/www/restricted/code_store/yii_fw/1.1.3/web/CController.php(300):

CInlineAction->run()

#10 /Raid/www/restricted/code_store/yii_fw/1.1.3/web/CController.php(278):

SiteController->runAction()

#11 /Raid/www/restricted/code_store/yii_fw/1.1.3/web/CController.php(257):

SiteController->runActionWithFilters()

#12

/Raid/www/restricted/code_store/yii_fw/1.1.3/web/CWebApplication.php(324):

SiteController->run()

#13

/Raid/www/restricted/code_store/yii_fw/1.1.3/web/CWebApplication.php(121):

CWebApplication->runController()

#14

/Raid/www/restricted/code_store/yii_fw/1.1.3/base/CApplication.php(135):

CWebApplication->processRequest()

#15 /Raid/www/restricted/www/sdms/DM/johnyii/index.php(12):

CWebApplication->run()

REQUEST_URI=/sdms/DM/johnyii/index.php?r=site/index

Any help will be greatly appreciated.

xx666xx · August 19, 2010, 5:41pm

Looks like your class name is wrong, CDBConnection should be CDbConnection. Note lowercase ‘b’.

Also, I think a better way to do this is to create a new model class that returns the correct db connection.

For instance, you have model ModelA which uses db. Create a subclass ModelB which extends ModelA but overrides the getDb method to return your second db (db2). Then you can read from ModelA and write to ModelB.

hdbgdz · August 19, 2010, 6:32pm

Thanks a lot. I can’t believe the problem was that simple. That saved me so much time, and thanks for the advice.

AustinGeek · March 27, 2013, 9:36pm

This worked perfectly for me on one system where both databases were on the same machine (localhost).

.../config/main.php




'db'=>array(

			'connectionString' => 'mysql:host=localhost;dbname=db1',

			'emulatePrepare' => true,

			'username' => '**',

			'password' => '**',

			'charset' => 'utf8',

		),

		'db2'=>array(

			'connectionString' => 'mysql:host=localhost;dbname=db2',

			'emulatePrepare' => true,

			'username' => '**',

			'password' => '**',

			'charset' => 'utf8',

			'class'	=> 'CDbConnection'

		),

But then I tried to use a similiar method to connect to 2 databases on different machines and it gave an error.

.../config/main.php




'db'=>array(

			'connectionString' => 'mysql:host=localhost;dbname=db1',

			'emulatePrepare' => true,

			'username' => '**',

			'password' => '**',

			'charset' => 'utf8',

		),

		'db2'=>array(

			'connectionString' => 'mysql:host=10.20.12.14;dbname=db2',

			'emulatePrepare' => true,

			'username' => '**',

			'password' => '**',

			'charset' => 'utf8',

			'class'	=> 'CDbConnection'

		),

The error I receive is the AltActiveRecord.php file followed by

"Fatal error: Class ‘AltActiveRecord’ not found in /var/www/q1media/protected/models/_base/BaseVideoTag.php on line 26 "

AltActiveRecord is defined in the BaseVideo.php class.




abstract class BaseVideo extends AltActiveRecord {

    

    public static function model($className = __CLASS__) {

        return parent::model($className);

    }


    public function tableName() {

        return 'db2.video';

    }

....

If I rename AltActiveRecord.php to something else, the view returns an error that makes sense. "Cannot open stream…"

Anyone with any clues ?

The servers are in the cloud and I can ping them, I can also connect to db2 from a php file on the webserver.

Thanks for any help!