{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2023,10,23]],"date-time":"2023-10-23T06:41:27Z","timestamp":1698043287346},"reference-count":18,"publisher":"Wiley","issue":"3","license":[{"start":{"date-parts":[[2007,3,21]],"date-time":"2007-03-21T00:00:00Z","timestamp":1174435200000},"content-version":"vor","delay-in-days":5923,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Systems &amp;amp; Computers in Japan"],"published-print":{"date-parts":[[1991,1]]},"abstract":"<jats:title>Abstract<\/jats:title><jats:p>In a relational database system based on the universal relation interface, users do not have to specify access paths when constructing universal queries. Moreover, users cannot control how to evaluate the queries efficiently (though they can construct usual queries, such as relational algebraic expressions, considering their processing costs). Thus, it is important for the system to evaluate given universal queries efficiently. This paper considers the representative instance of a database as a universal relation, and presents an optimization algorithm for evaluating a universal query for computing specified components of the tuples in the universal relation which satisfies a specified condition.<\/jats:p>","DOI":"10.1002\/scj.4690220303","type":"journal-article","created":{"date-parts":[[2007,7,7]],"date-time":"2007-07-07T20:30:08Z","timestamp":1183840208000},"page":"19-30","source":"Crossref","is-referenced-by-count":0,"title":["Optimizing universal queries in relational databases"],"prefix":"10.1002","volume":"22","author":[{"given":"Minoru","family":"Ito","sequence":"first","affiliation":[]},{"given":"Tadao","family":"Kasami","sequence":"additional","affiliation":[]}],"member":"311","published-online":{"date-parts":[[2007,3,21]]},"reference":[{"key":"e_1_2_1_2_2","doi-asserted-by":"crossref","unstructured":"P.AtzeniandE. P. F.Chan.Efficient query answering in the representative instance approach. 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Can we use the universal instance assumption without using nulls! Proc. ACM SIGMOD Int. Conf. Management of Data pp.108\u2013120(Apr.1981).","DOI":"10.1145\/582318.582336"},{"key":"e_1_2_1_17_2","doi-asserted-by":"publisher","DOI":"10.1145\/319983.319988"},{"key":"e_1_2_1_18_2","unstructured":"Y.Vassiliou.A formal treatment of imperfect information in database management. Tech. Rep. Univ. of Toronto CSRG\u2010123 (1980)."},{"key":"e_1_2_1_19_2","volume-title":"Principles of Database and Knowledge\u2010Base Systems","author":"Ullman J. D.","year":"1989"}],"container-title":["Systems and Computers in Japan"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/api.wiley.com\/onlinelibrary\/tdm\/v1\/articles\/10.1002%2Fscj.4690220303","content-type":"unspecified","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1002\/scj.4690220303","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,10,22]],"date-time":"2023-10-22T21:37:00Z","timestamp":1698010620000},"score":1,"resource":{"primary":{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/10.1002\/scj.4690220303"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1991,1]]},"references-count":18,"journal-issue":{"issue":"3","published-print":{"date-parts":[[1991,1]]}},"alternative-id":["10.1002\/scj.4690220303"],"URL":"https:\/\/doi.org\/10.1002\/scj.4690220303","archive":["Portico"],"relation":{},"ISSN":["0882-1666","1520-684X"],"issn-type":[{"value":"0882-1666","type":"print"},{"value":"1520-684X","type":"electronic"}],"subject":[],"published":{"date-parts":[[1991,1]]}}}