backend-php/models/HarvestModel.php

<?php

namespace Models;

class HarvestModel
{
    private \PDO $pdo;

    public function __construct()
    {
        if (!isset($GLOBALS['pdo']) || !$GLOBALS['pdo'] instanceof \PDO) {
            throw new \RuntimeException('Global PDO connection not initialized');
        }

        $this->pdo = $GLOBALS['pdo'];
    }

    public function getAll(): array
    {
        $stmt = $this->pdo->query('SELECT harvest_code, harvest_name FROM "harvest" ORDER BY harvest_name');
        return $stmt->fetchAll(\PDO::FETCH_ASSOC) ?: [];
    }
}