TCMMDB: a distributed multidatabase query system and its key technique implemention

With the amount of information exploding, the number of databases and information stored in the database increases very quickly. Those databases are more likely to be heterogeneous. There are many distributed databases systems to resolve this problem, but the main drawback is that they don't do well in database cooperation. We provide a general architecture of a distributed multidatabase query system: TCMMDB (traditional Chinese medicine multidatabase). We discuss key techniques such as distributed query plan generation, distributed query synchronization and distributed error handling in TCMMDB in relation to distributed databases.