Why Domain Entities Should Enforce Business Rules, Not Just Hold Data

A software engineering article on DEV Community argues that most codebases misuse the concept of 'domain entities' by treating them as little more than database rows with getters and setters. The author illustrates the problem using EU drivers'-hours compliance rules for a fleet management system, where legal driving limits are enforced nowhere inside the object itself. Drawing on Eric Evans' domain-driven design principles, the piece contends that a true entity should make invalid business states impossible to represent, rather than delegating all rule-checking to external service classes. The author presents a Driver aggregate in C# whose private setters and encapsulated compliance ledger prevent illegal state changes at the object level. Central to the argument is the idea that class and method names should mirror the language of the business domain, a practice Evans called 'ubiquitous language.'