Troubles updating data schema

Recently, I've been having issues when I change the structure of a database. I go to the administrator and update, but the schema doesn't refresh (it used to do so before).

I'm using a data model, I refresh the model, but the changes are not saved, and it crashes because it's looking for a field that doesn't exist (and I've already removed it), and on the other hand, the new fields don't appear...

I save the changes, but then....

What can I do?

Is there a way you can get into the app database and remove the field manually? BTW: which version are you using?

I think it's a problem with models.
When you update a table the changes are not automatically done in the model that still look for old fields and has no new ones.