Document handling. Create , View, Edit, Version

The document is only a Frame, the definition of the document.
You then should add version to the document, and attach the file corresponding to this verson of the document.

It should not be concidered as a File storage, but really as Content Management System, managing live of a document through its different versions.

Attachment is really different from document.

Attachement is just a file you link to an object.
It has no real value outside this object.
The best exemple is a screenshot attached to a ticket.

A document is an item that has real value outside other items.
For instance, the specification of a product is a document.
And this document can evolve : it is created in V1.0.
Then after small changes, new version V1.1 is released.
Then after major changes, new version V2.0 is released.
And so on...
You should not concider documents just as files, even if, in the end, files are managed.
And most important, you should never interact with documents outside ProjeQtOr GUI.

First you create a document, and describe it.
Then in the document, you just "add" a version. During this step, you will attach the file corresponding to the current version of the document.
Each time you change the docuemnt, you will just add a new version to upload the new file.
This way, you'll keep trace of every changed to the docuemnt : this is Document Management.