A method and system for conflict detection during construction of complex databases, such as a data model for driving or modeling a complex system. Components of a data model may be defined in rules that specify objects of various types and containing various elements. The rules are declarative, and may be stored on a computer-readable storage medium. Rule declarations or assertions include element definitions, values or ranges of values, inclusion requirements, and severity level conditions in the event that conflicts or errors are detected. Conflict checking takes account of compliance with type definitions, as well as a user identity and a phase of construction of the data model.