In this thesis, schema integration global query decomposition and optimization and global transactions manipulation in multidatabase systems are discoursed elaboratly . the algorithm which clears up one-to-one entity conflict and query process optimization algorithm are presented and analysiz . ed . the assurance strategy of transaction atomity and global deadlock resolution algorithm are also discussed in this thesis . at end of this thesis, based on domestic experiences and overseas experiences, a new multidatabase system model is presented by combining multidatabase system and corba technology, and security management mechanism is introduced in this model 本文對多數(shù)據(jù)庫系統(tǒng)中模式集成、全局查詢的分解和優(yōu)化以及全局事務(wù)的處理等問題進行了詳細而深入的論述,給出了一對一實體沖突的消解算法和查詢處理優(yōu)化算法,并對這些算法進行了分析;同時還論述了事務(wù)原子性的保證策略和全局死鎖的處理算法。最后,本文在借鑒國內(nèi)外經(jīng)驗的基礎(chǔ)上,把通用對象請求代理結(jié)構(gòu)技術(shù)與多數(shù)據(jù)庫系統(tǒng)結(jié)合起來,提出了一個新的多數(shù)據(jù)庫系統(tǒng)模型,在該模型中引入了安全管理機制。