Updated_at使用Laravel 4.2 DB Class的时间戳

Using Laravel 4.2 and the DB Class (I'm not allowed to use Eloquent)

How do I update a timestamp field with the DB Class in Laravel 4.2?

Table creation

CREATE TABLE posts
(
    id INTEGER PRIMARY KEY,
    title VARCHAR(255) NOT NULL,
    message VARCHAR(50000) NOT NULL,
    author VARCHAR(255) NOT NULL,
    avatar VARCHAR(255),
    created_at DATETIME DEFAULT (DATETIME(CURRENT_TIMESTAMP, 'LOCALTIME')),
    updated_at DATETIME DEFAULT (DATETIME(CURRENT_TIMESTAMP, 'LOCALTIME'))
);

Update row

$post = DB::update('UPDATE posts SET title=?,message=?,author=?,updated_at=? WHERE id=?',
    array(
        Input::get('title'),
        Input::get('message'),
        Input::get('author'),
        CURRENT_TIMESTAMP, <-- Throwing error, what do I put here???
        $id
    )
);

Throws this error

Use of undefined constant CURRENT_TIMESTAMP - assumed 'CURRENT_TIMESTAMP'

Discovered the answer.

I need to use the Carbon class included with Laravel 4.2

At the top of the file, put this:

use Carbon\Carbon;

Here's the query

$post = DB::update('UPDATE posts SET title=?,message=?,author=?,updated_at=? WHERE id=?',
    array(
        Input::get('title'),
        Input::get('message'),
        Input::get('author'),
        \Carbon\Carbon::now(),
        $id
    )
);