In database theory, relational algebra is a theory that uses algebraic structures for modeling data and defining queries on it with well founded semantics...
51 KB (6,354 words) - 10:15, 28 April 2025
In relational algebra, a projection is a unary operation written as Π a 1 , . . . , a n ( R ) {\displaystyle \Pi _{a_{1},...,a_{n}}(R)} , where R {\displaystyle...
7 KB (747 words) - 07:47, 26 March 2025
In relational algebra, a rename is a unary operation written as ρ a / b ( R ) {\displaystyle \rho _{a/b}(R)} where: R is a relation a and b are attribute...
2 KB (175 words) - 09:30, 11 July 2023
In relational algebra, a selection (sometimes called a restriction in reference to E.F. Codd's 1970 paper and not, contrary to a popular belief, to avoid...
8 KB (677 words) - 20:58, 25 January 2025
database. The relational calculus is similar to the relational algebra, which is also part of the relational model: While the relational calculus is meant...
3 KB (359 words) - 20:40, 5 December 2024
A relational database (RDB) is a database based on the relational model of data, as proposed by E. F. Codd in 1970. A Relational Database Management System...
32 KB (3,869 words) - 06:09, 17 April 2025
The relational model (RM) is an approach to managing data using a structure and language consistent with first-order predicate logic, first described in...
30 KB (4,196 words) - 15:00, 15 March 2025
directed graphs, where objects reference each other. Relational is tuples in tables with relational algebra. Tuples are data fields grouped into a "row" with...
17 KB (1,798 words) - 04:49, 30 April 2025
= { x ∈ X : x ∼ a } . {\displaystyle [a]=\{x\in X:x\sim a\}.} In relational algebra, if R ⊆ X × Y {\displaystyle R\subseteq X\times Y} and S ⊆ Y × Z {\displaystyle...
31 KB (4,473 words) - 11:36, 3 May 2025
Database normalization (redirect from Relational Database Normalization)
Database normalization is the process of structuring a relational database in accordance with a series of so-called normal forms in order to reduce data...
37 KB (2,918 words) - 07:42, 23 April 2025
Datalog (section Comparison to relational databases)
related to query languages for relational databases, such as SQL. The following table maps between Datalog, relational algebra, and SQL concepts: More formally...
59 KB (4,901 words) - 10:26, 17 March 2025
purpose of 1NF is to make the data model more flexible, to simplify the relational algebra and query language, and to enable further normalization levels which...
19 KB (2,539 words) - 07:05, 9 May 2025
the relational algebra projection operation. AS optionally provides an alias for each column or expression in the SELECT list. This is the relational algebra...
33 KB (3,100 words) - 20:59, 25 January 2025
various applications in computer science (such as in the theory of relational algebra), philosophy, formal semantics, and evolutionary dynamics. Its foundational...
54 KB (6,575 words) - 12:01, 1 May 2025
calculi (as well as relational algebra) are equivalent in expressive power.[citation needed] Subsequently, query languages for the relational model were called...
15 KB (2,303 words) - 03:50, 13 April 2025
Look up relational in Wiktionary, the free dictionary. Relational may refer to: Relational capital, the value inherent in a company's relationships with...
3 KB (414 words) - 06:06, 11 November 2020
theoretical properties that larger classes of queries (e.g., the relational algebra queries) do not share. The conjunctive queries are the fragment of...
15 KB (1,922 words) - 02:45, 12 January 2025
cover set of the relational algebra. The relational algebra allows data duplication in the relations that are the elements of the algebra. One of the efficiency...
2 KB (244 words) - 01:31, 17 April 2025
Octonion algebra Pre-Lie algebra Poisson algebra Process algebra Quadratic algebra Quaternion algebra Rees algebra Relation algebra Relational algebra Rota–Baxter...
2 KB (226 words) - 14:20, 21 November 2024
Universal algebra (sometimes called general algebra) is the field of mathematics that studies algebraic structures themselves, not examples ("models")...
25 KB (3,043 words) - 08:54, 11 February 2025
(sigma algebra), a refinement of sigma algebras Join (algebraic geometry), a union of lines between two varieties In computing: Join (relational algebra),...
2 KB (225 words) - 06:12, 2 May 2025
algebraic structures, such as groups, rings, etc. Elementary algebra, i.e. "high-school algebra" Abstract algebra Linear algebra Relational algebra Universal...
3 KB (415 words) - 17:08, 30 November 2021
be different on the surface: relational databases, multiple systems of formal logic or numerical problems of linear algebra. It allows the development of...
19 KB (2,296 words) - 12:44, 23 January 2025
into a new table. The operation corresponds to a join operation in relational algebra. Informally, a join stitches two tables and puts on the same row records...
42 KB (4,777 words) - 03:42, 30 March 2025
without accessing the stored hierarchy relation". The standard relational algebra and relational calculus, and the SQL operations based on them, are unable...
12 KB (1,527 words) - 12:00, 27 July 2024
NoSQL (redirect from Non-relational database)
"non-relational") refers to a type of database design that stores and retrieves data differently from the traditional table-based structure of relational databases...
30 KB (2,437 words) - 06:52, 9 May 2025
Haskell records. Relational databases may formally identify their rows (records) as tuples. Tuples also occur in relational algebra; when programming...
16 KB (2,224 words) - 06:56, 3 May 2025
variables. Its computational expressiveness is equivalent to that of relational algebra. Let (A, B, C) mean (Rank, Name, ID) in the Enterprise relation and...
4 KB (624 words) - 13:44, 22 April 2024
Logic programming (redirect from Relational programming)
in the development of relational databases that recursive queries cannot be expressed in either relational algebra or relational calculus, and that this...
85 KB (10,764 words) - 13:39, 8 May 2025
rename a file in various operating systems Rename (relational algebra), unary operation in relational algebra Company renaming, rename of a product Name change...
652 bytes (92 words) - 08:27, 14 October 2023