Foreign Key constraint is ignored inside transaction on iOS

https://github.com/yshrsmz/sqldelight-fktest

I have these two tables.

CREATE TABLE author (
    id INTEGER NOT NULL PRIMARY KEY,
    name TEXT NOT NULL,
    birthday TEXT NOT NULL
);

CREATE TABLE book (
    id INTEGER NOT NULL PRIMARY KEY,
    name TEXT NOT NULL,
    author_id INTEGER NOT NULL,
    FOREIGN KEY (author_id) REFERENCES author(id) ON DELETE CASCADE
);

and I’m trying to write a repository class which takes a list of books and insert those in one transaction.

fun save(books:List<Book>) {
	bookQueries.transaction {
		books.forEach { book ->
			bookQueries.insertOrReplace(...)
		}
	}
}

It should work just fine if corresponding author records exist, and it works as intended on Android. On iOS, above code does not respect Foreign Key constraint.

After some investigation I found out that on iOS, foreign keys are not working inside transaction. Below test case illustrates this.

@Test
fun `should fail as FK constraint is not satisfied - transaction`() {
    database.pragmasQueries.foreignKeysOn() // PRAGMA foreign_keys=1;

    val books = database.bookQueries.count().executeAsOne()
    val authors = database.authorQueries.count().executeAsOne()

    assertEquals(0, books)
    assertEquals(0, authors)

    var failed = false

    try {
        database.transaction {
            database.bookQueries.insert(id = book3.id, name = book3.name, author_id = book3.author_id)
        }
    } catch (e: Throwable) {
        println(e)
        failed = true
    }


    val books2 = database.bookQueries.count().executeAsOne()
    println("books count after insertion attempt: $books2")

    if (!failed) {
        fail("should throw exception")
    }
}

This test case passes on Android, and fails on iOS. And if I call insert statement without transaction, it passes on both platform.

[yshrsmz]

Confirmed it’s working on v1.1.4 with the code below. Thanks!

// iOS
val dbConfig = DatabaseConfiguration(
        name = "database.db",
        version = Schema.version,
        foreignKeyConstraints = true,
        create = { connection ->
            wrapConnection(connection) { Schema.create(it) }
        },
        upgrade = { connection, oldVersion, newVersion ->
            wrapConnection(connection) { Schema.migrate(it, oldVersion, newVersion) }
        }
    )

val driver = NativeSqlDriver(dbConfig)

// Android
val driver = AndroidSqliteDriver(
        schema = Database.Schema,
        context = context,
        name = "database.db",
        callback = object : AndroidSqliteDriver.Callback(Database.Schema) {
            override fun onConfigure(db: SupportSQLiteDatabase) {
                super.onConfigure(db)
                db.setForeignKeyConstraintsEnabled(true)
            }
        }
    )

[kpgalligan]

Some more info. Future versions of sqliter will have a db config flag for this. I also think I understand why fk pragma wasn’t working in transactions: https://stackoverflow.com/a/7360240/227313