This assumption is becoming increasingly unrealistic in the face of issues such as autonomy and heterogeneity. In addition, as databases become larger, more complex, and less centralized, and as organizations grow, change, and decentralize, the likelihood of having one individual with adequate global knowledge to make intelligent schema integration decisions becomes increasingly remote. Because the databases involved in integration efforts are generally decentralized, there will be a number of people with expertise about those component databases. When the burden of knowledge in the schema integration process is reduced to a local component schema, and decision-making regarding constraint satisfaction is reduced from the global to the local scale, the likelihood of one person or user group having adequate knowledge to make sound decisions is far greater than when complete global knowledge is required. The natural next step in database schema integration is a distributed technique which decentralizes the knowledge used in managing a decentralized information resource.
Cooperative problem solving or negotiation between cooperating experts offers such decentralization.
The purpose of such dialogue may be to reach agreement about allowable access and operations to component schemas, to agree upon the semantic relationships between structures in component schemas, or to satisfy constraints inherent to component database schemas. However, the concept of negotiation offers significant advantages throughout the process of database schema integration. Foremost of these is the potential for alleviating reliance upon an individual for global knowledge regarding all component schemas, and instead distributing reliance upon human expertise among local experts on component database schemas. The purpose of negotiation in this context is to allow schema integration and conflict resolution decisions to be made based upon localized goal, constraint, integration strategy, and interschema correspondence knowledge which need not be globally known. In so doing, the assumption of global knowledge may be discarded.