How to run multiple queries in a transaction about rel8

[ocharles]

Do I need to drop down to the level of the hasql package and write Statements for "begin transaction", "commit", etc?

Currently, yes. Rel8 intentionally currently only exports Connection -> IO () type functions to be as un-opinionated as possible. However, many people have suggested this is a pretty painful, and in practice we have wrapped this internally at CircuitHub with our own effect system to deal with this. It's unclear to me what the right API is, though. If you have any thoughts, I'm all ears!

[shane-circuithub]

I don't see any real downside to exporting the select, insert, etc. functions in Hasql's Statement monad rather than Connection -> IO (). People will have to depend on and import hasql to construct a Connection anyway, so they can easily use run to recover a Connection -> IO a function if that's what they'd rather work with. But it's much more convenient to use things like hasql-pool and hasql-transaction if we export Statements. I don't think this is even "opinionated" — it doesn't preclude somebody using a different solution — like I said, they can easily recover the current API with run if they wanted to use something different.

[ocharles]

Yea, I was also thinking of doing that - we already require people depend on hasql anyway to acquire a Connection. My point about being opinionated was more about offering something like MonadRel8 (something beyond plain functions).

[chris-martin]

It does seem like rel8 is currently straddling an awkward middle ground between being a full-fledged complete way to interact with your database, and being merely one part of the hasql ecosystem. I wonder if perhaps it would benefit from a clear decision one way or the other?