000			03661nam a22004215i 4500
999			_c387282 _d387282
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003			ES-MaUEC
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007			cr nn 008mamaa
008			220601s2011 sz | s |||| 0|eng d
020			_a9783031018831
024	7		_a10.1007/978-3-031-01883-1 _2doi
040			_aES-MaUEC _bspa _cES-MaUEC _dES-MaUEC
050		4	_aQA76.9.D3 _b2011 EB
100	1		_aBertossi, Leopoldo _eautor _4aut _4http://id.loc.gov/vocabulary/relators/aut _9687071
245	1	0	_aDatabase Repairs and Consistent Query Answering _cby Leopoldo Bertossi
250			_a1st edition 2011
264		1	_aCham _bSpringer International Publishing _c2011
300			_a1 recurso en línea (XV, 105 páginas)
336			_atexto _btxt _2rdacontent
337			_aelectrónico _bc _2rdamedia
338			_arecurso electrónico _bcr _2rdacarrier
347			_aarchivo de texto _bPDF
490	0		_aSynthesis Lectures on Data Management _x2153-5426
505	0		_aIntroduction -- The Notions of Repair and Consistent Answer -- Tractable CQA and Query Rewriting -- Logically Specifying Repairs -- Decision Problems in CQA: Complexity and Algorithms -- Repairs and Data Cleaning.
520			_aIntegrity constraints are semantic conditions that a database should satisfy in order to be an appropriate model of external reality. In practice, and for many reasons, a database may not satisfy those integrity constraints, and for that reason it is said to be inconsistent. However, and most likely, a large portion of the database is still semantically correct, in a sense that has to be made precise. After having provided a formal characterization of consistent data in an inconsistent database, the natural problem emerges of extracting that semantically correct data, as query answers. The consistent data in an inconsistent database is usually characterized as the data that persists across all the database instances that are consistent and minimally differ from the inconsistent instance. Those are the so-called repairs of the database. In particular, the consistent answers to a query posed to the inconsistent database are those answers that can be simultaneously obtained from all the database repairs. As expected, the notion of repair requires an adequate notion of distance that allows for the comparison of databases with respect to how much they differ from the inconsistent instance. On this basis, the minimality condition on repairs can be properly formulated. In this monograph we present and discuss these fundamental concepts, different repair semantics, algorithms for computing consistent answers to queries, and also complexity-theoretic results related to the computation of repairs and doing consistent query answering. Table of Contents: Introduction / The Notions of Repair and Consistent Answer / Tractable CQA and Query Rewriting / Logically Specifying Repairs / Decision Problems in CQA: Complexity and Algorithms / Repairs and Data Cleaning.
988			_aSynthesis Collection of Technology_2011
650		7	_2embne _9147823 _aRecuperación de la información
650		7	_2embne _9150569 _aSistemas de gestión de bases de datos
650		7	_2embne _9151605 _aLenguaje y lógica
776	0	8	_iPrinted edition: _z9783031007552
776	0	8	_iPrinted edition: _z9783031030116
856	4	0	_uhttps://go.openathens.net/redirector/universidadeuropea.es?url=https://doi.org/10.1007/978-3-031-01883-1 _zAcceso a este recurso digital (usuarios Universidad Europea de Madrid)
942			_2lcc _cLE
998			_b02/2023 _dz _esc _zSI