Create a basic database and the MVC files required to access the data in Yii2

Database_Basic.md

Yii2 Database (basic)

Database Table

 CREATE TABLE `country` (
  `code` CHAR(2) NOT NULL PRIMARY KEY,
  `name` CHAR(52) NOT NULL,
  `population` INT(11) NOT NULL DEFAULT '0'
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

INSERT INTO `country` VALUES ('AU','Australia',24016400);
INSERT INTO `country` VALUES ('BR','Brazil',205722000);
INSERT INTO `country` VALUES ('CA','Canada',35985751);
INSERT INTO `country` VALUES ('CN','China',1375210000);
INSERT INTO `country` VALUES ('DE','Germany',81459000);
INSERT INTO `country` VALUES ('FR','France',64513242);
INSERT INTO `country` VALUES ('GB','United Kingdom',65097000);
INSERT INTO `country` VALUES ('IN','India',1285400000);
INSERT INTO `country` VALUES ('RU','Russia',146519759);
INSERT INTO `country` VALUES ('US','United States',322976000);

Country Model (models/Country.php)

<?php

namespace app\models;

use Yii;

/**
 * This is the model class for table "country".
 *
 * @property string $code
 * @property string $name
 * @property integer $population
 */
class Country extends \yii\db\ActiveRecord
{
    /**
     * @inheritdoc
     */
    public static function tableName()
    {
        return 'country';
    }

    /**
     * @inheritdoc
     */
    public function rules()
    {
        return [
            [['code', 'name'], 'required'],
            [['population'], 'integer'],
            [['code'], 'string', 'max' => 2],
            [['name'], 'string', 'max' => 52]
        ];
    }

    /**
     * @inheritdoc
     */
    public function attributeLabels()
    {
        return [
            'code' => Yii::t('app', 'Code'),
            'name' => Yii::t('app', 'Name'),
            'population' => Yii::t('app', 'Population'),
        ];
    }
}

Country Controller (controllers/CountryController.php)

<?php

namespace app\controllers;

use yii\web\Controller;
use yii\data\Pagination;
use app\models\Country;

class CountryController extends Controller
{
    public function actionIndex()
    {
        $query = Country::find();

        $pagination = new Pagination([
            'defaultPageSize' => 5,
            'totalCount' => $query->count(),
        ]);

        $countries = $query->orderBy('name')
            ->offset($pagination->offset)
            ->limit($pagination->limit)
            ->all();

        return $this->render('index', [
            'countries' => $countries,
            'pagination' => $pagination,
        ]);
    }
}

Country View (views/country/index.php)

<?php
use yii\helpers\Html;
use yii\widgets\LinkPager;
?>
<h1>Countries</h1>
<ul>
<?php foreach ($countries as $country): ?>
    <li>
        <?= Html::encode("{$country->code} ({$country->name})") ?>:
        <?= $country->population ?>
    </li>
<?php endforeach; ?>
</ul>

<?= LinkPager::widget(['pagination' => $pagination]) ?>