How can I get an HTML5 webpage to use data from an already existing SQLite database?

I've created an SQLite database for one of my Unity apps that keeps track of how users use the app. I'm now trying to create a web page that takes that data and creates graphs out it. I've dug through a number of SQLite/javaScript tutorials and so far everything I've found has me create a new database. Is there a way to use my already existing database? If so, are there any good tutorials to walk me through the steps of setting things up?