query-store | Browser query in a Svelte store | Frontend Framework library

Cursors - Cursor Implementations: Application programming interface (API) server cursor

Application programming interface (API) server cursors API cursors support the API cursor functions in OLE DB and ODBC. API server cursors are implemented on the server. Each time a client application calls an API cursor function, the SQL Server Native Client OLE DB provider or ODBC driver transmits the request to the server for action against the API server cursor.

This is a good question. The system that is the source of these events is authoritative on the balance. The banking 'core' is a more traditional ledger with 2 phase commit (and most I've seen anyway have a nightly cycle process that determines if you're overdrawn). This core system could publish information transactions and other things that you could transform into NServiceBus. With this you could do all sorts of useful stuff like send text alerts, inform another system of this activity, subscribe a fraud early warning system, subscribe a rewards platform to accrue reward points etc.

The order of the events could get out of whack because of errors just as you say. That is a reality of asynch messaging and store and forward. Each receiving system would have to contend with that reality. You can re-order them in the destination through the time stamp if there is one but you cannot be sure you have them all at any given time.

With regard to an overdrawn condition, the best way to consider that is to source that as a separate event from the authoritative core. It's the only system that knows and could push an 'Account overdrawn' sort of event that itself could trigger a notice, a fee, a note to the branch manager...