Hi Teoh,
Thanks for asking your question on the forum. Your assumption is not correct; you local app does not share it's database with the cloud node. This would not be desirable as well, as the cloud and local app may differ in version.
What you could do, is use Postgres on your local machine. Potentially, you can create a backup of this database and upload it to your cloud node (if you are not on the free tier). The most common setup however involves two separate databases, in which you need to ‘maintain’ both your local database, as your cloud database. It's more common to download a backup from your cloud node, so you can use it locally as a starting point.
Hopefully, this helps