Relational Algebra - Example
The nnary and Binary operators in relational Algebra.
What is the utility of relational algebra relational calculas name some software's based on these concept?"
Oracle8i
This is a big question. I you enter 'relational algebra' in a search engine, you will find many sites which go over this. Wikipedia usually takes a very high level abstract approach. The link below seems fairly easy to understand.
Relational Algebra - Example
The nnary and Binary operators in relational Algebra.
What is the utility of relational algebra relational calculas name some software's based on these concept?"
Oracle8i
This is a big question. I you enter 'relational algebra' in a search engine, you will find many sites which go over this. Wikipedia usually takes a very high level abstract approach. The link below seems fairly easy to understand.
Which relational algebra operators can be applied to a pair of tables that are not union compatible
Which relational algebra operators can be applied to a pair of tables that are not union compatible
Edward M'William Patterson has written: 'Elementary abstract algebra' -- subject(s): Algebra 'Elementary abstract algebra [by] E.M. Patterson [and] D.E. Rutherford' -- subject(s): Abstract Algebra, Algebra, Abstract
CHUT
Relation algebra is a procedural language where relation calculus is non-procedural languageRelational algebra, an offshoot of first-orderlogic (and of algebra of sets), deals with a set of finitaryrelations (see also relation (database)) which is closed under certain operators. These operators operate on one or more relations to yield a relation. Relational algebra is a part of computer science.Relational calculus consists of two calculi, the tuplerelational calculus and the domain relational calculus, that are part of the relational model for databases and provide a declarative way to specify database queries. This in contrast to the relational algebra which is also part of the relational model but provides a more procedural way for specifying queries.The relational algebra might suggest these steps to retrieve the phone numbers and names of book stores that supply Some Sample Book:1. Join books and titles over the BookstoreID.2. Restrict the result of that join to tuplesfor the book Some Sample Book.3. Project the result of that restriction over StoreNameand StorePhone.The relational calculus would formulate a descriptive, declarative way:Get StoreNameand StorePhonefor supplies such that there exists a title BK with the same BookstoreIDvalue and with a BookTitlevalue of Some Sample Book.The relational algebra and the relational calculus are essentially logically equivalent: for any algebraic expression, there is an equivalent expression in the calculus, and vice versa.This result is known as Codd'stheorem
John A. Beachy has written: 'Abstract algebra' -- subject(s): Abstract Algebra, Algebra, Abstract 'Introductory lectures on rings and modules' -- subject(s): Modules (Algebra), Noncommutative rings
Gertrude Ehrlich has written: 'Fundamental concepts of abstract algebra' -- subject(s): MATHEMATICS / Algebra / Abstract, Abstract Algebra 'Fundamental concepts of abstract algebra' -- subject(s): Abstract Algebra 'Fundamental concepts of abstract algebra' -- subject(s): MATHEMATICS / Algebra / Abstract, Abstract Algebra