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2. Relational algebra - Wikipedia

   en.wikipedia.org/wiki/Relational_algebra

   Lecture Notes: Relational Algebra – A quick tutorial to adapt SQL queries into relational algebra; Relational – A graphic implementation of the relational algebra; Query Optimization This paper is an introduction into the use of the relational algebra in optimizing queries, and includes numerous citations for more in-depth study.

3. Relation algebra - Wikipedia

   en.wikipedia.org/wiki/Relation_algebra

   A relation algebra (L, ∧, ∨, −, 0, 1, •, I, ˘) is an algebraic structure equipped with the Boolean operations of conjunction x∧y, disjunction x∨y, and negation x −, the Boolean constants 0 and 1, the relational operations of composition x•y and converse x˘, and the relational constant I, such that these operations and constants satisfy certain equations constituting an ...

4. List of set identities and relations - Wikipedia

   en.wikipedia.org/wiki/List_of_set_identities_and...

   11 Notes. 12 Citations. 13 References. ... Download as PDF; Printable version; In other projects ... show that it is a Boolean algebra. ...

5. Relation (mathematics) - Wikipedia

   en.wikipedia.org/wiki/Relation_(mathematics)

   Since relations are sets, they can be manipulated using set operations, including union, intersection, and complementation, leading to the algebra of sets. Furthermore, the calculus of relations includes the operations of taking the converse and composing relations .

6. Codd's theorem - Wikipedia

   en.wikipedia.org/wiki/Codd's_theorem

   Codd's theorem states that relational algebra and the domain-independent relational calculus queries, two well-known foundational query languages for the relational model, are precisely equivalent in expressive power. That is, a database query can be formulated in one language if and only if it can be expressed in the other.

7. Category:Relational algebra - Wikipedia

   en.wikipedia.org/wiki/Category:Relational_algebra

   Print/export Download as PDF; Printable version; In other projects Wikimedia Commons; Wikidata item; ... Pages in category "Relational algebra"

8. Projection (relational algebra) - Wikipedia

   en.wikipedia.org/.../Projection_(relational_algebra)

   Projection is relational algebra's counterpart of existential quantification in predicate logic. The attributes not included correspond to existentially quantified variables in the predicate whose extension the operand relation represents. The example below illustrates this point.

9. Composition of relations - Wikipedia

   en.wikipedia.org/wiki/Composition_of_relations

   Another form of composition of relations, which applies to general -place relations for , is the join operation of relational algebra. The usual composition of two binary relations as defined here can be obtained by taking their join, leading to a ternary relation, followed by a projection that removes the middle component.