The objective of the presented approach is to increase productivity of the design process by informing designers about the correlations to parallel work and by practising collaborative work. A cooperative design process is support by a shared design database called the Active Semantic Network (ASN). The ASN is an active, distributed, and object-oriented database system that supports the de nition of constraints that are evaluated by a rule-based approach. Constraints and locking con icts are used to nd out when the work of designers coincides and they have to adapt their work to results of colleagues. Additional to the support of information exchange, a cooperative transaction model provides several cooperation mechanisms to allow users to exchange partial results and share common data.