Technical Perspective: Allocating Isolation Levels to Transactions in a Multiversion Setting

Among the ways a database management system adds value, is the transaction abstraction, where the application coder can group together multiple data accesses that collectively perform one meaningful real-world activity. The platform will provide the "ACID"properties (atomic, consistent, isolated and durable) so the whole transaction happens like a single event. The mechanisms that allow this appearance include crash recovery and rollback (usually based on log entries) and concurrency control (typically involving locks).