I am creating a web app, where user will have posibility of defining their data structure/ schema. for example Name, Address [Array], Age, Gender (*optional field).

Later they can load data in web application. This will be validated against the schema created.

What would be the best way to achive this?

another question is: in runtime if data is large, is it good idea to use sqlite or someother database to store these data, and application will use it later from database.

Thanks in advance

I am able to store data into fixed fields name. I want more abstraction so that user can define their own data schema at runtime.