MigrateMissingDatabaseSource.php

<?php

namespace Drupal\migrate_missing_database_test\Plugin\migrate\source;

use Drupal\Core\Database\Query\SelectInterface;
use Drupal\migrate\Plugin\migrate\source\SqlBase;

/**
 * A simple migrate source for the missing database tests.
 *
 * @MigrateSource(
 *   id = "migrate_missing_database_test",
 *   source_module = "migrate_missing_database_test",
 *   requirements_met = true
 * )
 */
class MigrateMissingDatabaseSource extends SqlBase {
    
    /**
     * {@inheritdoc}
     */
    public function query() : SelectInterface {
        $field_names = [
            'id',
        ];
        $query = $this->select('missing_database', 'm')
            ->fields('m', $field_names);
        return $query;
    }
    
    /**
     * {@inheritdoc}
     */
    public function fields() : array {
        $fields = [
            'id' => $this->t('ID'),
        ];
        return $fields;
    }
    
    /**
     * {@inheritdoc}
     */
    public function getIds() : array {
        return [
            'id' => [
                'type' => 'integer',
            ],
        ];
    }

}