Domain Modeling Made Functional

Transactions

All the code so far has been of the form “one aggregate = one transaction.” But in many situations, we have a number of things that need to be saved together atomically—all or nothing.

Some data stores support transactions as part of their API. Multiple calls to the service can be enlisted in the same transaction, like this:

let connection = new SqlConnection()
let transaction = connection.BeginTransaction()

// do two separate calls to the database
// in the same transaction
markAsFullyPaid connection invoiceId
markPaymentCompleted connection paymentId

// completed
transaction.Commit()

Some data stores only support transactions as long as everything is done in a single connection. In practice, that means ...