作者: 刺激 時(shí)間: 2025-3-21 23:54
Constraint Databases, Queries, and Query Languagesnal calculus, the relational algebra, and .. We show how a computationally complete constraint query language can be obtained by augmenting the constraint relational calculus with basic programming language features. We look into some basic model-theoretic issues concerning the constraint relational作者: tolerance 時(shí)間: 2025-3-22 01:48 作者: vitrectomy 時(shí)間: 2025-3-22 07:00
Query Safety with Constraintsts expressible through queries in the relational calculus, for example, is limited in a number of ways: They have PTIME data complexity, and their expressiveness is well understood. Although relational calculus queries may not return finite results, a natural subclass of the relational calculus does作者: 聚集 時(shí)間: 2025-3-22 10:28
Aggregate Languages for Constraint Databasesry languages give a natural analog of relational calculus in the geometric context, a crucial question concerns how to extend standard aggregation constructs from the relational model to the geometric setting. This question has two components.作者: 咒語(yǔ) 時(shí)間: 2025-3-22 15:32 作者: 咒語(yǔ) 時(shí)間: 2025-3-22 21:04 作者: Radiculopathy 時(shí)間: 2025-3-22 23:27
Euclidean Query Languagesssive power of language FO + . is too limited. One of these limitations is that FO + . is incapable of expressing queries involving Euclidean distance, betweenness, and collinearity. For example, a query such as “Return all cities in Belgium that are further than 100 km away from Brussels” cannot be作者: 無(wú)表情 時(shí)間: 2025-3-23 05:01 作者: 戲法 時(shí)間: 2025-3-23 07:25
Linear Repeating Pointstime can easily be introduced as additional attributes in the relational model. Of course, specific operations need to be performed with temporal attributes, such as dealing with date formats, but such operations are not really problematic, and have long been available in commercial systems. Neverth作者: Dendritic-Cells 時(shí)間: 2025-3-23 10:31
Constraint Algebras, which is then optimized and evaluated. As we have seen in Section 2.4.4, if we consider unrestricted databases, the classical equivalence between the algebra and the calculus carries over easily. Furthermore, all the algebraic operations described in in Section 2.4.4 can be effectively evaluated o作者: GROWL 時(shí)間: 2025-3-23 14:05 作者: FLIT 時(shí)間: 2025-3-23 19:52 作者: 多山 時(shí)間: 2025-3-23 23:18 作者: aggravate 時(shí)間: 2025-3-24 05:23 作者: AIL 時(shí)間: 2025-3-24 08:50 作者: 盤(pán)旋 時(shí)間: 2025-3-24 13:03
Radiographic Analysis of the Femurconjunction of constraints from an appropriate language (for example, linear arithmetic constraints), and that many of the features of the relational model could be extended in an appropriate way. In particular, standard query languages such as those based on first-order logic and . could be extended, at least in principle, to such a model.作者: 歡騰 時(shí)間: 2025-3-24 15:31 作者: Glossy 時(shí)間: 2025-3-24 20:17
y of the field of constraint databases. Constraint databases are a fairly new and active area of database research. The key idea is that constraints, such as linear or polynomial equations, are used to represent large, or even infinite, sets in a compact way. The ability to deal with infinite sets m作者: Ccu106 時(shí)間: 2025-3-25 01:13
Radiographic Analysis of the Femurressiveness is well understood. Although relational calculus queries may not return finite results, a natural subclass of the relational calculus does; namely the class of .. This class gives guarantees of finite output, and is complete in this respect, capturing all relational calculus queries whose outputs are always finite, the . queries.作者: Anguish 時(shí)間: 2025-3-25 05:03 作者: 航海太平洋 時(shí)間: 2025-3-25 09:26
Diagnostic of Urogenital Tuberculosis,e algebra and the calculus carries over easily. Furthermore, all the algebraic operations described in in Section 2.4.4 can be effectively evaluated over constraint databases, and that the data complexity bounds discussed in Chapter 4 also apply to the algebra.作者: EXPEL 時(shí)間: 2025-3-25 13:54
Introductionconjunction of constraints from an appropriate language (for example, linear arithmetic constraints), and that many of the features of the relational model could be extended in an appropriate way. In particular, standard query languages such as those based on first-order logic and . could be extended, at least in principle, to such a model.作者: badinage 時(shí)間: 2025-3-25 17:15
Expressive Power: The Finite Casebases whose elements come from the set .. For example, FO + . and FO + ., the relational calculus with linear and polynomial constraints, can be considered as query languages over ordinary relational databases that store numbers.作者: Wordlist 時(shí)間: 2025-3-25 20:48
Selection of a Surgical Strategy some generality. We shall see that equivalence of relational calculus queries on constraint databases is typically undecidable, but that that equivalence is decidable in the special case of conjunctive queries on constraint databases.作者: Biofeedback 時(shí)間: 2025-3-26 02:32 作者: Thyroid-Gland 時(shí)間: 2025-3-26 06:00 作者: BLA 時(shí)間: 2025-3-26 10:37 作者: Vulnerable 時(shí)間: 2025-3-26 12:58 作者: negligence 時(shí)間: 2025-3-26 17:31
s. In par- ticular, the terminology and the style of presentation have been standardized, and there are multiple cross-references between the chapters. The idea of constraint databases goes back to the late Paris Kanellakis.978-3-642-08542-0978-3-662-04031-7作者: 燒烤 時(shí)間: 2025-3-26 22:43 作者: NORM 時(shí)間: 2025-3-27 02:37
Book 2000posed to a collection of individual surveys. In par- ticular, the terminology and the style of presentation have been standardized, and there are multiple cross-references between the chapters. The idea of constraint databases goes back to the late Paris Kanellakis.作者: 移動(dòng) 時(shí)間: 2025-3-27 06:16 作者: 可以任性 時(shí)間: 2025-3-27 12:41 作者: 極端的正確性 時(shí)間: 2025-3-27 15:57
Radiographic Analysis of the Femur on . and Constraint Logic Programming (CLP). The original motivation was to combine work in these two areas, with the goal of obtaining a database-style, optimizable version of constraint logic programming. The key idea was that the notion of a tuple in a relational database could be replaced by a 作者: Condyle 時(shí)間: 2025-3-27 18:10 作者: crumble 時(shí)間: 2025-3-27 22:17
Selection of a Surgical Strategyted as a constraint.in free variables ..,..., ... A relation . is then represented by a formula.stating that the interpretation of a tuple (.. ,..., ..) must be among the .Consequently, constraint query languages, over a structure ., can be considered as query languages over ordinary relational data作者: adj憂(yōu)郁的 時(shí)間: 2025-3-28 02:23 作者: Goblet-Cells 時(shí)間: 2025-3-28 07:31
Selection of a Surgical Strategyry languages give a natural analog of relational calculus in the geometric context, a crucial question concerns how to extend standard aggregation constructs from the relational model to the geometric setting. This question has two components.作者: 按時(shí)間順序 時(shí)間: 2025-3-28 10:41
https://doi.org/10.1007/978-3-319-03982-4n for “.base . programs.” In Section 2.8 we gave the basic definitions for ., and we also saw that the language is not closed for important constraint classes such as linear equalities. We have also seen some results on restricting the language, and the resulting expressive power, in Section 4.4.1.作者: IOTA 時(shí)間: 2025-3-28 15:05 作者: 綠州 時(shí)間: 2025-3-28 20:21 作者: textile 時(shí)間: 2025-3-29 01:34 作者: 治愈 時(shí)間: 2025-3-29 04:38
Genetic Aspects of Uncommon Diseasestime can easily be introduced as additional attributes in the relational model. Of course, specific operations need to be performed with temporal attributes, such as dealing with date formats, but such operations are not really problematic, and have long been available in commercial systems. Neverth作者: 蔓藤圖飾 時(shí)間: 2025-3-29 07:56
Diagnostic of Urogenital Tuberculosis,, which is then optimized and evaluated. As we have seen in Section 2.4.4, if we consider unrestricted databases, the classical equivalence between the algebra and the calculus carries over easily. Furthermore, all the algebraic operations described in in Section 2.4.4 can be effectively evaluated o作者: AV-node 時(shí)間: 2025-3-29 14:16 作者: 圍巾 時(shí)間: 2025-3-29 18:07
Aggregate Languages for Constraint Databasesry languages give a natural analog of relational calculus in the geometric context, a crucial question concerns how to extend standard aggregation constructs from the relational model to the geometric setting. This question has two components.作者: PUT 時(shí)間: 2025-3-29 23:38
and Constraintsn for “.base . programs.” In Section 2.8 we gave the basic definitions for ., and we also saw that the language is not closed for important constraint classes such as linear equalities. We have also seen some results on restricting the language, and the resulting expressive power, in Section 4.4.1.作者: 破譯 時(shí)間: 2025-3-30 01:42 作者: compel 時(shí)間: 2025-3-30 05:08
I/O-Efficient Algorithms for CDBstabases, it is possible to design theoretically . practically efficient algorithms. In addition, we show that certain problems are . hard with the result that no theoretically efficient algorithms are possible for them. This chapter has three parts:作者: 音樂(lè)等 時(shí)間: 2025-3-30 12:00 作者: Immunotherapy 時(shí)間: 2025-3-30 13:37 作者: 行乞 時(shí)間: 2025-3-30 19:03
Parkinson’s Disease in Intensive Care Unithem are of primary interest. Such differences in scope and emphasis are crucial, as they affect the data model, the query language, and performance. This chapter presents a survey of results concerning topological queries in spatial databases. Motivated primarily by GIS, we focus on semi-algebraic regions in the two-dimensional plane.
