How to update app with latest changes

Hi everyone,
I want to know how to update my custom app without losing the data related to it .
because when I update json file of my custom app
then using terminal windows with the following command :
bench --site site-name uninstall-app app-name
then use
bench --site site-name install-app app-name
it will delete all the records.It seem a fresh installtion of app.
So can any one tell me. How I can update my whole app without losing the record ?
waiting for the fast response

Karuna Nidhan

A post was merged into an existing topic: How to update custom app with latest changes