Please use this identifier to cite or link to this item:
https://ah.lib.nccu.edu.tw/handle/140.119/69126
DC Field | Value | Language |
---|---|---|
dc.contributor | 資科系 | en_US |
dc.creator | 陳良弼 | zh_TW |
dc.creator | Chiu,Jui-Shang;Chen,Arbee L.P. | en_US |
dc.date | 1997 | en_US |
dc.date.accessioned | 2014-08-21T06:47:37Z | - |
dc.date.available | 2014-08-21T06:47:37Z | - |
dc.date.issued | 2014-08-21T06:47:37Z | - |
dc.identifier.uri | http://nccur.lib.nccu.edu.tw/handle/140.119/69126 | - |
dc.description.abstract | 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 | Data & Knowledge Engineering,22(1),39-65 | en_US |
dc.subject | Incomplete information; Disjunctive information; Partial values; Query language semantics; Relational algebra; Relational databases | en_US |
dc.title | Manipulation of exclusive disjunctive data in relational databases | en_US |
dc.type | article | en |
item.fulltext | With Fulltext | - |
item.grantfulltext | restricted | - |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
item.languageiso639-1 | en_US | - |
item.openairetype | article | - |
item.cerifentitytype | Publications | - |
Appears in Collections: | 期刊論文 |
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