What “in one file” means
runtime/storage/database.sqliteThis file is not a text document to edit. SQLite organizes tables, indexes, and transactions itself. The application talks to it through PHP's PDO driver.
SQLite or a database server?
PHPAML Data supports all four SQL drivers. Starting with SQLite does not lock the architecture: the entity and DbContext remain the same when the connection changes.
An important Git distinction
The reproducible schema belongs in migrations and therefore Git. database.sqlite contains real data and remains under runtime, normally ignored. Code explains how to rebuild the database; it does not publish private contents.
Check your understanding: Should you send database.sqlite to a colleague?
Usually no. Share migrations and, if needed, a demonstration seeder without private data.