Relational Algebra

This article presents an overview of Stream Algebra, a research field that has emerged after the birth of Relational Algebra used in Database Management Systems (DBMS). When Stream Data appeared and needed to be processed in real-time, the role of Stream Algebra became evident. Since the rise of Big Data, this field has received attention in recent years, the role of Stream Algebra has been further demonstrated.

7p visarada 28-04-2025 1 1   Download

Có 2 loại xử lý Làm thay đổi dữ liệu (cập nhật) Thêm mới, xóa và sửa Không làm thay đổi dữ liệu (rút trích) Truy vấn (query) Thực hiện các xử lý Đại số quan hệ (Relational Algebra) Biểu diễn câu truy vấn dưới dạng biểu thức Phép tính quan hệ (Relational Calculus) Biểu diễn kết quả SQL (Structured Query Language)

80p tet0202 19-02-2013 157 22   Download

Đại số quan hệ (tiếng Anh: relational algebra) dùng phổ biến trong lí thuyết cơ sở dữ liệu quan hệ là một bộ các toán tử và các quy tắc tương ứng có thể được sử dụng để thao tác trên các toán học (relation) và tạo ra kết quả là một quan hệ khác. Trước đây, đại số quan hệ ít được quan tâm cho đến khi Edgar F. Codd đưa ra mô hình dữ liệu quan hệ (relational model) vào năm 1970. Từ đó đến nay, đại số quan hệ được xem là nền tảng cho các ngôn...

81p quynhngasp 30-03-2010 1165 272   Download

The main contents of the chapter consist of the following: The relational algebra, unary relational operations, relational algebra operations from set theory, binary relational operations, ER-to-Relational mapping algorithm, mapping EER model constructs to relations.

40p nanhankhuoctai10 23-07-2020 24 3   Download

We prove a blow-up formula for cyclic homology which we use to show that infinitesimal K-theory satisfies cdh-descent. Combining that result with some computations of the cdh-cohomology of the sheaf of regular functions, we verify a conjecture of Weibel predicting the vanishing of algebraic K-theory of a scheme in degrees less than minus the dimension of the scheme, for schemes essentially of finite type over a field of characteristic zero. Introduction The negative algebraic K-theory of a singular variety is related to its geometry. ...

26p dontetvui 17-01-2013 58 8   Download

We prove that the existence of an automorphism of finite order on a Q-variety X implies the existence of algebraic linear relations between the logarithm of certain periods of X and the logarithm of special values of the Γ-function. This implies that a slight variation of results by Anderson, Colmez and Gross on the periods of CM abelian varieties is valid for a larger class of CM motives. In particular, we prove a weak form of the period conjecture of Gross-Deligne [11, p. 205]1 .

29p tuanloccuoi 04-01-2013 67 9   Download

We devise a new criterion for linear independence over function fields. Using this tool in the setting of dual t-motives, we find that all algebraic relations among special values of the geometric Γ-function over Fq [T ] are explained by the standard functional equations. Contents 1. Introduction 2. Notation and terminology 3. A linear independence criterion 4. Tools from (non)commutative algebra

78p tuanloccuoi 04-01-2013 60 7   Download

To the memory of Rodica Simion The goals of this paper are two-fold. First, we prove, for an arbitrary finite root system Φ, the periodicity conjecture of Al. B. Zamolodchikov [24] that concerns Y -systems, a particular class of functional relations playing an important role in the theory of thermodynamic Bethe ansatz. Algebraically, Y -systems can be viewed as families of rational functions defined by certain birational recurrences formulated in terms of the root system Φ.

43p tuanloccuoi 04-01-2013 51 8   Download

ON THE ALGEBRAIC DIFFERENCE EQUATIONS un+2 un = ψ(un+1 ) IN R+ , RELATED TO A FAMILY ∗ OF ELLIPTIC QUARTICS IN THE PLANE G. BASTIEN AND M. ROGALSKI Received 20 October 2004 and in revised form 27 January 2005 We continue the study of algebraic difference equations of the type un+2 un = ψ(un+1 ), which started in a previous paper. Here we study the case where the algebraic curves related to the equations are quartics Q(K) of the plane. We prove, as in “on some algebraic difference equations un+2 un = ψ(un+1 ) in R+ , related to families of...

35p sting12 10-03-2012 38 5   Download

SMOOTH AND DISCRETE SYSTEMS—ALGEBRAIC, ANALYTIC, AND GEOMETRICAL REPRESENTATIONS ˇ FRANTISEK NEUMAN Received 12 January 2004 What is a differential equation? Certain objects may have different, sometimes equivalent representations. By using algebraic and geometrical methods as well as discrete relations, different representations of objects mainly given as analytic relations, differential equations can be considered.

10p sting12 10-03-2012 35 4   Download

In 1991, David Gale and Raphael Robinson, building on explorations carried out by Michael Somos in the 1980s, introduced a three-parameter family of rational recurrence relations, each of which (with suitable initial conditions) appeared to give rise to a sequence of integers, even though a priori the recurrence might produce non-integral rational numbers. Throughout the '90s, proofs of integrality were known only for individual special cases. In the early '00s, Sergey Fomin and Andrei Zelevinsky proved Gale and Robinson's integrality conjecture.

13p thulanh8 19-09-2011 73 5   Download

Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học tạp chí Journal of Operator Theory đề tài: Về cấu trúc của (BCP)-nhà khai thác và đại số có liên quan...

11p matuot_266 27-08-2011 56 4   Download

Tuyển tập các báo cáo nghiên cứu khoa học ngành toán học tạp chí Journal of Operator Theory đề tài: Về cấu trúc của (BCP) nhà khai thác và đại số có liên quan...

23p matuot_266 27-08-2011 46 4   Download