Cleanest & safest way to include prepopulated .sqlite file in Swift app - swift

Question

The file needs to be read and write later. On Android I used Room & RoomAssetHelper.
I understand the basic logic that I need to include it in the project assets and then copy it to somewhere accessible for the app at first start. But I want to avoid writing these things manually and risking making an error (I am not too confident with reading files & DBs).
All of the answers that I find are from people giving quick & dirty advice on how to manually code the logic for this. I would like to do it on a clean & professional level.
Is there a library that would do most of the "risky" work for me?
(Meaning import & copy the .sqlite file, so I can start using it in my code)
I found GRDB.swift, but I cannot figure out if it supports prepopulated files.

Answer 1

Please stop looking for a magical library that will do all of this for you automatically.
What you need to do yourself without any SQLite library?
Add your prepopulated database.sqlite as an asset to your project.
When the app launches, check if the database.sqlite file is present at the expected location (inside your app's documents directory for example). You can check this using FileManager APIs.
If the file exists at the expected path, you are fine, no need to copy any file.
If the database.sqlite file does not exist at the expected path, you need to copy your database.sqlite file at the path using FileManager APIs.
CAUTION :
Be aware that in this step, you may encounter an error while copying the file. This should not happen for most cases. In rare caes that it does happen, you should adjust your app accordingly - indicate to user somehow that initialization failed, free some space on your phone, restart app etc.
Steps 2-4 need to be checked on every app launch - put this logic somewhere close your app startup process. If all of above instructions are followed and you succeed either via step 3 OR 4, you now have the database.sqlite file where you want it to be.
Where the SQLite library comes in?
At this point, you can use any library that suits your purpose and you feel comfortable with.
As you mentioned GRDB.swift, it allows you to specify a custom path for your database file. Copy-pasting the current version minimal setup code here for reference.
import GRDB
// 1. Open a database connection
let dbQueue = try DatabaseQueue(path: "/path/to/database.sqlite")
// 2. Define the database schema
try dbQueue.write { db in
try db.create(table: "player") { t in
t.autoIncrementedPrimaryKey("id")
t.column("name", .text).notNull()
t.column("score", .integer).notNull()
}
}
// 3. Define a record type
struct Player: Codable, FetchableRecord, PersistableRecord {
var id: Int64
var name: String
var score: Int
}
// 4. Access the database
try dbQueue.write { db in
try Player(id: 1, name: "Arthur", score: 100).insert(db)
try Player(id: 2, name: "Barbara", score: 1000).insert(db)
}
let players: [Player] = try dbQueue.read { db in
try Player.fetchAll(db)
}