Observability

TableObserver records table writes (via triggers) when a transaction finishes. toFlow re-runs a query when those tables change.

val users: Flow<List<User>> =
    userAdapter.select().toFlow(db) { list() }

(userAdapter.select() where (User.name like "A%"))
    .toFlow(db, runQueryOnCollect = false) { singleOrNull() }

runQueryOnCollect = true (default) emits immediately on collect. Set false if the first single() would throw on an empty table.

Writes must go through a DBFlow transaction so the observer runs. For a one-shot coroutine transaction as a Flow:

db.beginTransactionAsync { userAdapter.select().list() }.toFlow()

Android: LiveData, Paging, RxJava.