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題名 Manipulation of exclusive disjunctive data in relational databases
作者 陳良弼
Chiu,Jui-Shang;Chen,Arbee L.P.
貢獻者 資科系
關鍵詞 Incomplete information; Disjunctive information; Partial values; Query language semantics; Relational algebra; Relational databases
日期 1997
上傳時間 21-Aug-2014 14:47:37 (UTC+8)
摘要 In this paper, we propose an extended relational model, named Pv-table, for representing exclusive disjunctive data (i.e., there exists a set of possible values for a data item, and exactly one of the possible values is true) by associating partial values and variables with attributes. While a partial value denotes the set of possible values, a variable serves as an identifier for the true value of the data item. Identifiers can be used to determine the equi-relationship among partial values. The relational operators are extended to manipulate Pv-tables. We show that the set-based query evaluation on Pv-tables is sound and complete for queries consisting of extended selection, union, intersection, Cartesian product and join. We also show that useful algebraic properties are preserved in our model. A disjunctive (resp. conjunctive) query can be replaced by the extended union (resp. intersection) of the two corresponding subqueries. These properties provide a more natural interpretation of queries. They also facilitate query decomposition process for optimizing distributed queries. These properties are not preserved for many other extended models.
關聯 Data & Knowledge Engineering,22(1),39-65
資料類型 article
dc.contributor 資科系en_US
dc.creator (作者) 陳良弼zh_TW
dc.creator (作者) Chiu,Jui-Shang;Chen,Arbee L.P.en_US
dc.date (日期) 1997en_US
dc.date.accessioned 21-Aug-2014 14:47:37 (UTC+8)-
dc.date.available 21-Aug-2014 14:47:37 (UTC+8)-
dc.date.issued (上傳時間) 21-Aug-2014 14:47:37 (UTC+8)-
dc.identifier.uri (URI) http://nccur.lib.nccu.edu.tw/handle/140.119/69126-
dc.description.abstract (摘要) In this paper, we propose an extended relational model, named Pv-table, for representing exclusive disjunctive data (i.e., there exists a set of possible values for a data item, and exactly one of the possible values is true) by associating partial values and variables with attributes. While a partial value denotes the set of possible values, a variable serves as an identifier for the true value of the data item. Identifiers can be used to determine the equi-relationship among partial values. The relational operators are extended to manipulate Pv-tables. We show that the set-based query evaluation on Pv-tables is sound and complete for queries consisting of extended selection, union, intersection, Cartesian product and join. We also show that useful algebraic properties are preserved in our model. A disjunctive (resp. conjunctive) query can be replaced by the extended union (resp. intersection) of the two corresponding subqueries. These properties provide a more natural interpretation of queries. They also facilitate query decomposition process for optimizing distributed queries. These properties are not preserved for many other extended models.en_US
dc.format.extent 1662912 bytes-
dc.format.mimetype application/pdf-
dc.language.iso en_US-
dc.relation (關聯) Data & Knowledge Engineering,22(1),39-65en_US
dc.subject (關鍵詞) Incomplete information; Disjunctive information; Partial values; Query language semantics; Relational algebra; Relational databasesen_US
dc.title (題名) Manipulation of exclusive disjunctive data in relational databasesen_US
dc.type (資料類型) articleen