[feature] Dao independent transactions

[otopba]

Sometimes you need to make a transaction that will work with several DAO or will have a lot of logic. I would like to have separate methods for starting and ending a transaction. Now, having only an annotation, this is not possible

Thank you!

[vitusortner]

What would you think of something similar to the following? We could add a member function on FloorDatabse that can be used for executing DAO functions inside a transaction.

database.runInTransaction(() {
  // DAO invocations
});

[otopba]

@vitusortner
Yes, it can be done that way. But then how can we say that the transaction is successful or not? If there was no exception, is the transaction successful?

[mqus]

Usually, yes. I don't know why that shouldn't be the case.

[mqus]

I want to add, though, that if we want to add support for database.runInTransaction then we will have to give the inner function its own database (backed by the transaction). So the actual invocation would look like this:

database.runInTransaction((transactionDB) async {
  // DAO invocations
  transactionDB.someDao.findEntriesInTable("value");
});

or this (just using a function reference instead of a closure):

database.runInTransaction(withTransaction);

Future<void> withTransaction(MyDB transactionDB) async{
  // DAO invocations
  transactionDB.someDao.findEntriesInTable("value");
}

This would fit nicely into #360, too.

[NikoBoerger]

Are there any updates on that? :)

[vitusortner]

Unluckily not. In case you're interested, feel free to open a PR that implements the desired functionality.