| Project/Area Number |
11680416
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
情報システム学(含情報図書館学)
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| Research Institution | NARA INSTITUTE OF SCIENCE AND TECHNOLOGY |
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Principal Investigator |
ITO Minora Graduate School of Information Sciences, Professor, 情報科学研究科, 教授 (90127184)
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| Co-Investigator(Kenkyū-buntansha) |
SAKUMURA Yuuichi Graduate School of Information Sciences, NARA INSTITUTE OF SCIENCE AND TECHNOLOGY Research Associates, 情報科学研究科, 助手 (50324968)
ISHII Shin Graduate School of Information Sciences, Associate Professor, 情報科学研究科, 助教授 (90294280)
中西 隆一 奈良先端科学技術大学院大学, 情報科学研究科, 助手 (60263232)
石原 靖哲 大阪大学, 大学院・基礎工学研究科, 講師 (00263434)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2000)
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| Budget Amount *help |
¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 2000: ¥1,000,000 (Direct Cost: ¥1,000,000)
Fiscal Year 1999: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | Semi-structured Data / Object-Oriented Database / Type Dependency / Inference Problem / Path Expression |
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| Research Abstract |
1. In usual databases, it is assumed that the stored data must be in a fixed format for the underlying database schema that is designed in advance. In semi-structured data, on the other hand, the data (that would have a common concept) may not have the same structure, so that it is difficult to design a fixed database schema in advance. In this project, we focus on types of properties, introduce a constraint that can expresses a type information including ambiguity of semi-structured data, and aim to solve a number of basic problems on such a constraint.
2. We extend the constraint called SC (specialization constraint) that express a type of a property so as to be able to express a constraint which a semi-structured data should satisfy. By the extension, an SC may have a set of path expressions.
3. For the inference problem on SCs (which decides if an SC σ is a logical consequence of a set of SCs Σ), we obtain a set of inference rules that is sound and complete.
4. We obtain a sufficient condition such that the inference problem is partially decidable. Similarly, for the co-problem (that is, negation) of the inference problem, we obtain a sufficient condition such that the co-problem is partially decidable.
5. By the result above, if the set of path expressions in an SC is context-free, then the inference problem is undecidable. If the set of path expressions in an SC is regular, then the inference problem is decidable.
6. As for the navigation problem of a path expression (which decides if there is a database that contains a path which we can navigate along the given path expression), we obtain a similar result as above.
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