const classafMongo::MongoSeqs

(Service) - Creates sequential sequences of Ints as an alternative to using BSON ObjectIds.

A Mongo Collection stores the last ID created for sequences. An atomic findAndUpdate operation both increments and returns the relevant document.

By keeping the last IDs stored in the database it ensures the IDs are persisted between system restarts and that multiple clients can generate unique IDs.

While there is an overhead in generating new IDs, Int IDs have the advantage of using less space in indexes, being easier to work with in web applications and they're generally nicer to look at!