Rules (Regelwerke) are the business rule engine in Nuclos 5 for logic that other mechanisms do not cover. Masks steer entry. State models steer lifecycle. Attributes and references on the Businessobjekt steer structure. When validation, calculation, side effect, or integration go beyond that, rules apply. For decision-makers: targeted automation where low-code configuration ends, without forking the Nuclos core.

What the rules engine delivers

Rules encapsulate business logic as configuration and code within the platform. Typical triggers are save, state change, and scheduled jobs. There are client rules and server rules: client-near for immediate operator effect, server-side for binding logic and background runs. That keeps automation on the case, not in a parallel script world.

This is process automation with guardrails. Rules live in the Nuclet. Source and configuration stay tied to your instance. Platform framing: Nuclos 5 as a platform.

When rules are needed and when not

Not every requirement needs a rule. Required fields and defaults often belong on the Businessobjekt. Allowed transitions belong in the state model. Mask layout steers operation. Rules come when calculation, cross-check, message, or integration cannot be solved cleanly otherwise. Anyone who packs everything into rules loses the benefits of low-code. Anyone who uses rules where mechanisms end keeps the model maintainable.

For executives: scope and testability count. For IT: compile, runtime behaviour, and release count. Both belong in the same governance frame as the rest of configuration.

Nuclosian and rules

Nuclosian writes Java rules and creates them on the server, where they are compiled. There is no dry run. In business language you describe the effect: “An order may be delivered only after it is paid.” After a change to an existing rule, a line compare with Undo appears while the previous version is still held in memory. That does not replace business alignment. It shortens the path from statement to running rule. Entry points: Nuclosian: first steps.

Technical wiki: Regelwerke. Configuration and engine reference there. Here the lexicon answer: the rules engine is for logic beyond mask and state.

What the rules engine is not

Rules are not a blank cheque for undocumented special logic and not a substitute for process clarification. Uncontrolled agents in productive end-user operations without a config gate are not the usage pattern. Equally wrong: rules as a shadow ERP beside the model. The engine works on the Businessobjekt and on state. Anyone who only wants chat on legacy systems does not need rules. Anyone who wants to automate individual ERP under control does.