POLYGEN DATA MODEL,LANGUAGE AND QUERY PROCESSING IN IMDBS SYSTEM
IMDBS系统中的多源数据模型、语言及查询处理

IMDBS is an integrated multi-databases system which can integrate information and data in existing local heterogeneous database systems and supply global users with shared Integrated Information.And all local database applications can still execute on the Integrated database,thus localautonomymlght be preserved.IMDBSbasedonthe source tag Integration mechanism adopted the non first normal form(NF2)data model as its polygendata mode.PSQL/NF,a SQL like polygendata language,Is defined for users to use it to manipulate database conveniently. The system can Integrate traditionaldatabases such as relational,hlerarchlcal and network databases bottomup and managedistributed data top-down,so it fundamentally resolves the conflict between global dl.tribution transparency and local autonomy in heterogeneous distributed database systems.This paper mainly describesthe polygen data model,the polygen data language and theimplementatlontechnlques ofqueryprocessingofthe IMDBSsystem.