Critical decisions. DB !

I arrived at the crux of my app: the alignment of db between two devices with installed my project.

This is an important asset (since I'm not going to publish it for free).

The initial idea was to link the two (?) devices directly together, without going through the web. Not all devices have wifi-direct. The ideal, in this case, it would also avoid the use of local network, then the normal wifi. So BlueTooth (it is slow but it's probably fast enough).

But the sync is obviously impossible.

Use a server: I have no idea where to start (except the absurd to create one at home!). I do not think that there are sites that allow you to install a db, handle it to your liking and maybe even free, is not it?

Use an email of the users? Forcing them to send an email with the changes to other users?

To be or not to be ... Well, better to be

P.S. I meant sites with MS Server! (I don't know MySql-PHP-Apache, & C.)

You can try Parse, there are libraries for device and for B4j http://www.b4x.com/android/forum/threads/parse-library-–-push-notifications-and-cloud-storage.29024/.
I'm using it only to update and sync the db which are loaded to the device during installation so the activity is low and free.

derez said:

You can try Parse, there are libraries for device and for B4j http://www.b4x.com/android/forum/threads/parse-library-–-push-notifications-and-cloud-storage.29024/.
I'm using it only to update and sync the db which are loaded to the device during installation so the activity is low and free.

Click to expand...

I do not know what it is (I had read somewhere on this site about this parse, but the word made me immediately think of some kind of text parser) and this is one more reason to give it a look .

Many thanks

WOW.

I'm reading the post of Agraham and unless I'm hallucinating, if my poor english (with the great help of Google Translate) they do not deceive me, this is a tool that will solve all my problems.

Again many thanks, derez (and Erel + Agraham too!!!)

P.S. (I do not think having to open a new thread, Erel ) ... but I do not remember, from school, the Saxon genitive:
"post of Agraham" or "Agraham's post" ? Ok, grrrr, i'll search it


DAMN!
It is not enough to solve my problem, or not for free.
Agrahm wrote:
"...the first being free as long as you keep within their limits which are one million API Requests per month, one million Push Notifications per month and one Gigabyte of storage use..."

But my app will be installed on 100,000,000 devices (at least)

(since I'm not going to publish it for free)

Click to expand...

my app will be installed on 100,000,000 devices (at least)

Click to expand...

So what are few dollars to pay to Parse for it ?

derez said:

So what are few dollars to pay to Parse for it ?

Click to expand...

Same as One cent for Scrooge McDuck !

I need help from a genius (or saint )

I'm thinking so solve this "problem" forcing the user to use his email; better, my app should use his email address and send (in background) a text file (zipped/encrypted?) containing every new Query and timestamp.

At startup of my app, it should (or can, if user set this as preference) "read" (fetch? i don't know the right term) for new updating-email.

I'm completly out?