如何在CI4的Helper函数中访问数据库

use CodeIgniter\Database\Database;

$database = Database::connect();

$query = $database->query('SELECT * FROM table_name');
$result = $query->getResult(); // 获取查询结果集

$data = [
    'column1' => 'value1',
    'column2' => 'value2',
];

$database->table('table_name')->insert($data);

$data = [
    'column1' => 'new_value1',
    'column2' => 'new_value2',
];

$database->table('table_name')->where('id', $id)->update($data);

$database->table('table_name')->where('id', $id)->delete();

$query = $database->table('table_name')
    ->select('column1, column2')
    ->where('column1', 'value1')
    ->orderBy('column2', 'DESC')
    ->limit(10)
    ->get();

$result = $query->getResult();