User - De ned Aggregates in Database
نویسنده
چکیده
User-deened aggregates can be the linchpin of sophisticated datamining functions and other advanced database applications , but they nd little support in current database systems including Object-Relational databases. Three serious limitations of current databases are (i) the inability of introducing new aggregates (e.g., by coding them in a procedural language as proposed in SQL3), (ii) the inability of returning partial results during computation (e.g., to support online aggregation), and (iii) the inability of using aggregates in recursive queries|e.g., to express Bill of Materials (BoM) applications and optimized graph searches. This paper proposes a uniied solution to these problems, and discusses practical and theoretical aspects of this powerful addition to database languages.
منابع مشابه
User - De ned Aggregates for DataminingHaixun
User-deened aggregates can be the linchpin of sophisticated datamining functions and other advanced database applications. This is demonstrated by our eecient implementation on DB2 of SQL3 user-deened aggregates extended with early returns, which we have used to implement several data mining algorithms. Aggregates with early returns are monotonic and can thus be used freely in recursive queries.
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