A minimal example of how to set up a backend SQLite store with Tauri.
I'm using Rusqlite to provide a nicer wrapper for SQLite.
In setup() inside main.rs, we initialize the database and put the Connection inside Tauri state.
initialize_database() creates the expected path for our .sqlite file, using app_handle.path_resolver().app_data_dir(). It uses PRAGMA user_version to track the DB version. 0 means newly-created, and 1 means created. Further versions can be added as the schema changes. upgrade_database_if_needed() checks user_version and upgrades inside a transaction, to maintain database integrity.
state.rs sets up the Tauri app state to hold the Connection object, to be re-used across the app. It provides some trait methods to grab the Mutex for the connection, run an operation and release it again.
Inside Tauri commands we can supply a app_handle: AppHandle argument, which will be automatically populated by the Tauri framework. From there we can call our db() trait method on app_handle to do database operations. Anything returned from the closure will be passed through.
let my_result = app_handle.db(|db: &Connection| /* Do something with the DB connection and return a value */);I pass the AppHandle through to any other modules that need it, so they also have access to the Connection. You can also call app_handle.clone() in case you run into ownership issues.