Normalization Of The Relationship Between Mode Of Distributed Applications

In distributed system which is created by the replication technology of SQL-Server, users can access, update both local data and remote replicative data. But because of the delay through network, local concurrency mechanism can't be aware of real-time operational status of other computers. Even if there are conflicts in the system, each site can't gain real-time information. Although SQL-Server provides the method to check and solve the conflicts, it still has no capability to avoid conflicts. The problem mentioned above is more difficult to resolve in distributed database system.In distributed application based on replication technology, there exist two kinds of replicative conflicts: update conflict and primary key conflict. We can find out a satisfied relation scheme to avoid conflicts by researching these two kinds of conflicts. This paper presents the theory of standardizing the distributed application and defines two Distributed Normal Form (DNF), 1DNF and 2DNF. And then it brings forward the way to standardizing the distributed system. Firstly, this paper provides the criterion to determine the scheme can avoid conflicts or not during the period of relation scheme design. Secondly, for a conflict-existing scheme, this paper guide us how to standardize the scheme in order to achieve 2DNF, a satisfied relation scheme which can avoid conflicts.