Optimizing Entity Join Queries by Extended Semijoins in a Wide Area Multidatabase Environment
نویسندگان
چکیده
In this paper we consider processing entity join queries in a wide area multidatabase environmen t where the query processing cost is dominated by the cost of data transmission An entity join oper ation integrates tuples representing the same en tities from di erent relations in which inconsistent data may exist The semijoin technique has been successfully used in a distributed database system to reduce the cost of data transmission However it cannot be directly applied to process the entity join query In this paper an extension of the tradition al semijoin named extended semijoin is proposed to reduce the cost of data transmission for entity join query processing in a wide area multidatabase envi ronment
منابع مشابه
Entity Join Optimization in Mutidatabase Systems
Heterogeneities exist in a multidatabase environment For example a real world entity may be di erently represented in relations of di erent databases In particular keys of these relations may be incompatible In this paper we develop an entity join operator named EJ operator which can be used to join two relations on their compatible incompatible keys By this join if an enti ty is represented in...
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