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| Title | Manipulation of exclusive disjunctive data in relational databases |
| Creator | 陳良弼 Chiu,Jui-Shang;Chen,Arbee L.P. |
| Contributor | 資科系 |
| Key Words | Incomplete information; Disjunctive information; Partial values; Query language semantics; Relational algebra; Relational databases |
| Date | 1997 |
| Date Issued | 21-Aug-2014 14:47:37 (UTC+8) |
| Summary | 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. |
| Relation | Data & Knowledge Engineering,22(1),39-65 |
| Type | 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) | 1997 | en_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),39-65 | en_US |
| dc.subject (關鍵詞) | Incomplete information; Disjunctive information; Partial values; Query language semantics; Relational algebra; Relational databases | en_US |
| dc.title (題名) | Manipulation of exclusive disjunctive data in relational databases | en_US |
| dc.type (資料類型) | article | en |