Migrating from Sqflite

[aleripe]

Hi, it's me again! After converting all my data layer I was trying to test the migration on an existing database.
I'm currently using sqflite and my database is at version 24 (I don't really know where this value is stored as I can't find it in the database).
The problem is when I run my updated app with sqlite_async (sqlite3) it tries to execute all the migrations as it thinks database is at version 0 but it fails finding the tables already exist. I see this library creates a migration table where it stores all the values.

Has someone already tried to migrate from sqflite to sqlite_async (sqlite3)? Thanks!

EDIT: sqflite stores database version in PRAGMA user_version

[aleripe]

I don't know if this method could be modified to check PRAGMA user_version if $migrationTable has not been found...

Future<int> getCurrentVersion(SqliteWriteContext db) async {
    try {
      final currentVersionRow = await db.getOptional(
          'SELECT ifnull(max(id), 0) as version FROM $migrationTable');
      int currentVersion =
          currentVersionRow == null ? 0 : currentVersionRow['version'];
      return currentVersion;
    } on SqliteException catch (e) {
      if (e.message.contains('no such table')) {
        return 0;
      }
      rethrow;
    }

}

[rkistner]

The migrations in sqlite_async stores more than just the version number, and PRAGMA user_version could have been used for different purposes, so we can't do that check in the core library.

However, you can add a check directly to the app's migrations, such as:

final migrations = SqliteMigrations()
  ..add(SqliteMigration(1, (tx) async {
    final userVersion = (await db.get('PRAMGA user_version'))['user_version'];
    if (userVersion < 1) {
      await tx.execute(
          'CREATE TABLE test_data(id INTEGER PRIMARY KEY AUTOINCREMENT, data TEXT)');
    } else {
       // Already migrated in sqflite, ignore
    }
  }))

[aleripe]

Thanks a lot Ralf, this is a good suggestion. I'll try to see if this suits my needs, otherwise I'll have to fork your library. Thanks again! Cheers