Please Help me Sir/Madam choosing the Coding language and their specific lessons..

Question

I am a member of an Association consisting 1500 members.. Presently we are maintaining our data in ms excel.. we are planning to advance to app based advancement.. The responsibility is on mine.. I want to make an andoid based app
1. That will input data from around 1500 users over internet.
2. will store data at cloud or something for free
3. They can output based on certain criteria (presently the filtering, count, sum functions of excel are fine.. app version of these are needed)
4. An admin panel to edit the data..
5. if possible mailing the all members from admin panel.
6. The app will be free so no google store service is needed.
7. We may in future go for website also.. the data should be used their also..

I have basic knowledge of C language and VBA macro.. please suggest me the coding languages and lessons for it.. I dont want to go for online excel to app converters. as it will be hard for maintenance or little changes if needed.

Answer 1

i think REST api is the first thing you need for data transaction between app and server.

as for the serverside language nodejs with express framework, or php with slim framework should be decent.

there's alot of resource on the internet to look for, just go to your trusted search engine type something like
"nodejs rest api"
or
"php rest api with slim framework"

database, moving on to proper dbms isnt a bad idea. modifying excel file in server can be tedious and probably unsafe with many user on the system.
meanwhile most of dbms can handle multiple user by default.