如何在“干净架构”中实现“SQL 事务”？

Question

I am working on an Express-based (Nodejs) API that uses MySQL for data persistence. I have tried to follow the CLEAN ARCHITECTURE proposed by Sir R.C. Martin.

Long story short:-

There are some crop vendors and some users. A user can request an order of some crops with a defined quantity from a vendor. This puts the order in PENDING state. Then the vendor will confirm the orders he/she gets from the user.

Domain/Entity -> CROP, Use-case -> add, remove, edit, find, updateQty

Domain/Entity -> ORDER, Use-case -> request, confirm, cancel

I have to implement a confirm order functionality

• I have an already recorded order with ordered item list in my DB (order in the pending state)
• Now on confirming order action I need to subtract each item quantity from respective crop present in the DB record, with a check that no value turns negative (ie no ordered qty is more than present qty)
• If it is done for all the items under a "transaction cover" then I have to commit the transaction
• Else revert back to the previous state (ie rollback)

I know how to run Mysql specific transactions using "Sequelize", but with a lot of coupling and poor source code architecture. (If I do it that way, then DB won't be like plugin anymore)

I am not able to understand how to do this while maintaining the architecture and at what layer to implement this transaction thing, use-case/data-access, or what?

Thanks in advance

Answer 1

I recommend keeping the transaction in the "adapters layer" by using "unit of work" pattern. This way the database remains a plug-in to the business logic.