Simple Magento2 example of retrieving and displaying a custom table field?

Question

I have a custom table in my Magento2 database and can not find a simple working example of how to connect, retrieve, and display the field data in a Magento2 page.

This one mostly works but is incomplete because it stops at fetching the field but doesn't show how to actually display the field on the webpage: http://webkul.com/blog/magento2-write-custom-mysql-query-without-using-model/

Can someone please provide a complete example?

Answer 1

You have mentioned a tutorial that explains CRUD operation without model, but it is not good practice using object manager.

let me explain crud operation with model, it is very simple. This is very important concept in Magento.

For example Let's consider the below table structure

For CRUD operation you need to create three things

1. Model

In Model you need to initialize resource model

app/code/<vendor>/<module>/Model/Example.php

<?php
namespace <vendor>\<module>\Model;
use Magento\Framework\Model\AbstractModel;
class Example extends AbstractModel
{
    /**
     * Define resource model
     */
    protected function _construct()
    {
    $this->_init('<vendor>\<module>\Model\ResourceModel\Example');
    }
}

2. Resource Model

In Resource model you need to initialize table name and primary key.

app/code/<vendor>/<module>/Model/ResourceModel/Example.php

<?php
namespace <vendor>\<module>\Model\Resource;
class Example extends \Magento\Framework\Model\ResourceModel\Db\AbstractDb
{
    /**
     * Define main table
     */
    protected function _construct()
    {
    $this->_init('custom_table_name', 'id');   //here id is the primary key of custom table
    }
}

3. Collection

In collection you need to define Model and Resource Model.

app/code/<vendor>/<module>/Model/ResourceModel/Example/Collection.php

<?php
namespace <vendor>\<module>\Model\ResourceModel\Example;

class Collection extends \Magento\Framework\Model\ResourceModel\Db\Collection\AbstractCollection
{
    /**
     * Define model & resource model
     */
    protected function _construct()
    {
    $this->_init(
        '<vendor>\<module>\Model\Example',
        '<vendor>\<module>\Model\ResourceModel\Example'
    );

    }
}

That's it, now you can able to fetch table value in any block using dependency injection.

For eg: Get and Set Data in Block

Kindly note, we pass <module>\<vendor>\Model\ExampleFactory in constructor, but none of the file will be found in that location

In Magento 2, each CRUD model has a corresponding factory class. All factory class names are the name of the model class appended with the word “Factory”.Since, our model class is named <module>/<vendor>/Model/Example this means our factory class is named <module>/<vendor>/Model/ExampleFactory

………………….
………………….

protected $_exampleFactory; 

public function __construct( <vendor>\<module>\Model\ExampleFactory $db)
{
    $this->_exampleFactory = $db;
}
public function anyMethodYouWant()
{
//set value
$this->_exampleFactory->create()->setData(array('event_name' => 'xyz', 'event_imgurl' => 'xyz',...............))->save();

//get value
$data=$this->_exampleFactory->create()->getCollection();
foreach ($data as $d ) 
{
       echo $d->getEventImgurl();   //table field event_imgurl
       echo $d->getEventName();    //table field event_name
}

}

after that you can call this block method in your template file

<?php $block->anyMethodYouWant(); ?>