J
Read the Memento Database wiki @ http://wiki.mementodatabase.com/index.php/Main_Page.
To use Memento like a relational system, do the following:
* Make your links (relationships) one-to-many. By default, they are many-to-many.
* Make your Entry Names unique. By default, uniqueness is not required.
Libraries are related, not pages. For libraries with lots of fields, one can group them into pages and subheaders. The user can then swipe or tab among these sets of fields within an entry.
Each library contains an Entry Name. The individual field that is the first one entered, by default, is set to the Entry Name, but that distinction may be moved to any other field. Also, multiple fields can be set to Entry Name. If the library is set to have unique entry names, then an entry name acts like a primary key whenever the Library participates in a one-to-many relationship. If there are multiple entry name fields, the Entry Name fields are concatenated (with an intervening space) to form the overall primary key.
The mobile edition stores its data locally, and these local libraries, with their associated files, may be synchronized to the Memento Cloud. The desktop edition work off of and stores its creations in the Memento Cloud (only).
In terms of external data transfer, Memento can import from and export to CSV files and can synchronize with Google Sheets stored on Google Drive. Of course, there are limitations, as Memento has features not supported by Google Sheets and vice versa.
I have used the desktop edition very little so far, so it is hard for me to counsel you on it. Hopefully someone else will fill in those blanks.