Magento2 – Get Database Connection

databasemagento2.2.2table

I wish to have code equivalent in Magento 2.

The below one is Magento 1

$resource = Mage::getSingleton('core/resource'); $connection =
$resource->getConnection('core_read');

I need the above code in Magento 2.

Best Answer

Without a Mage class, how does a developer instantiate model or magento-singleton object? The Mage::getModel and Mage::getSingleton methods have been retired, and in their place Magento has a new “Object Manager” object.

Right now this object manager is a PHP singleton, which you can grab with the following call.

$object_manager = MagentoCoreModelObjectManager::getInstance();

Magento is moving towards an architecture where this object will be automatically available in appropriate places as the _objectManager property.

$this->_objectManager

protected $_resource;
public function __construct(
   ...
   \Magento\Framework\App\ResourceConnection $resource
   ...
   ) {
   $this->_resource = $resource;
}

$connection = $this->_resource->getConnection();

For more information check alanstorm.com

Related Solutions

Magento 1.9 – How to Use a Different DB Connection for Collections

A quick check (see test case below) actually shows what you are doing should be just peachy.
For that reason, I suspect some error in your configuration. Please edit your post to include your collection class with at least it's __construct and _construct methods.
Also, if you are not using the sales/order resource model, please include it with it's constructor methods, too.

UPDATE:
I just noticed you are using $resource->getConnection('reportingdb_read'); in your constructor.
In the configuration XML the connection is called <externaldb_read>.
Note: reportingdb_read != externaldb_read

Maybe thats just a copy & paste error in your post, but if not, you have to use
$resource->getConnection('externaldb_read');
If that isn't the issue, please update your post, again, and I'll help dig further.

// Test to confirm a connection set via setConnection() on a 
// Mage_Reports_Model_Resource_Order_Collection instance is used
// to load the collection data.
class Reports_CollectionTest extends PHPUnit_Framework_TestCase
{
    public static function setUpBeforeClass()
    {
        require_once 'app/Mage.php';
        Mage::setIsDeveloperMode(true);
        Mage::app('admin');
    }

    protected function getConnectionMock()
    {
        $mockSelect = $this->getMockBuilder('Varien_Db_Select')
            ->disableOriginalConstructor()
            ->getMock();

        $mockConn = $this->getMockBuilder('Varien_Db_Adapter_Pdo_Mysql')
            ->disableOriginalConstructor()
            ->getMock();

        $mockConn->expects($this->once())
            ->method('select')
            ->will($this->returnValue($mockSelect));

        $mockConn->expects($this->once())
            ->method('fetchAll');

        return $mockConn;
    }

    /**
     * @test
     */
    public function testCollectionConnection()
    {
        $mockCon = $this->getConnectionMock();

        $collection = new Mage_Reports_Model_Resource_Order_Collection;
        $collection->setConnection($mockCon);

        $this->assertSame($mockCon, $collection->getConnection());
        $collection->load();
    }
}

Magento 1.8 Database – Problems Saving Data to DB – Fatal Error: Cannot Call Abstract Method

Try making your Pricebinc_Shipping_Model_Resource_Shipmentlist class look like this:

class Pricebinc_Shipping_Model_Resource_Shipmentlist extends Mage_Core_Model_Resource_Db_Abstract {
    protected function _construct()
    {
        $this->_init('shipping/shipmentlist', 'autoid');
    }
}

So don't call the parent::_construct method and the first parameter of _init should contains a slash not an underscore.

Best Answer

Related Solutions

Magento 1.9 – How to Use a Different DB Connection for Collections

Magento 1.8 Database – Problems Saving Data to DB – Fatal Error: Cannot Call Abstract Method

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