Temporal-Lobe
发表于 2025-3-23 12:17:54
ons with safe negation or inequality, which correspond to well-known classes of relational algebra queries. We provide a set of decidability, undecidability and complexity results for answering queries of the above languages over various classes of Description Logics knowledge bases. In general, suc
火车车轮
发表于 2025-3-23 17:56:19
Alfred Kleinknecht in this paradigm that (1) have increasing expressive power, and (2) illustrate robust conceptual restrictions thus exhibiting interesting additional properties. These properties suggest that we consider our sublanguages as candidates for “query languages”. Viewing query languages as restrictions of
critic
发表于 2025-3-23 18:42:39
ies for implementing atomic data types. These two strategies place incomparable constraints on the conflict relations between concurrent operations resulting in incomparable synchronization protocols. Also, the conflict relations used are usually static in the sense that the algorithms do not use th
Contort
发表于 2025-3-24 01:13:15
Alfred Kleinknecht in this paradigm that (1) have increasing expressive power, and (2) illustrate robust conceptual restrictions thus exhibiting interesting additional properties. These properties suggest that we consider our sublanguages as candidates for “query languages”. Viewing query languages as restrictions of
注射器
发表于 2025-3-24 03:38:29
Alfred Kleinknechtecial block-wise nested-loop join . Independent of any cost function is the dynamic programming approach to join ordering. The number of alternatives this approach generates is known as well . Further, it is known that for some cost functions — those fulfilling the ASI property — the probl
Magisterial
发表于 2025-3-24 10:15:59
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Pert敏捷
发表于 2025-3-24 13:25:35
Alfred Kleinknechtl applications accessing data at more than one .. An important research issue in . is query optimization. The query optimization problem in . is quite different from the case of distributed database system (.) since, due to schema heterogeneity and local autonomy of component ., is not possible to a
FAST
发表于 2025-3-24 18:16:56
lean queries), and gives a meaningful definition of the expressive power of a query language in a single finite model..The notion of . of a boolean query language . in a finite model A is defined by considering two values: the Kolmogorov complexity of the isomorphism type of A, equal to the length o
走路左晃右晃
发表于 2025-3-24 22:59:04
Alfred Kleinknechtries. One of the most important decisions in designing a data warehouse is the selection of materialized views to be maintained at the warehouse. The goal is to select an appropriate set of views that minimizes total query response time and the cost of maintaining the selected views, given a limited
Mercurial
发表于 2025-3-25 00:40:41
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