Which relational algebra operators can be applied to a pair of tables that are not union compatible
Relational Algebra - Example
The nnary and Binary operators in relational Algebra.
SELECT, PROJECT, DIVIDE, PRODUCT, and JOIN
What is the utility of relational algebra relational calculas name some software's based on these concept?"
Which relational algebra operators can be applied to a pair of tables that are not union compatible
Relational Algebra - Example
The nnary and Binary operators in relational Algebra.
SELECT, PROJECT, DIVIDE, PRODUCT, and JOIN
What is the utility of relational algebra relational calculas name some software's based on these concept?"
yes
Oracle8i
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
Which relational algebra operators can be applied to a pair of tables that are not union compatible
CHUT
Yes, relational algebra is non-procedural. Relational algebra comprises a collection of objects and operators on these objects. The operators may be used to specify which rows in the relations, or combinations or relations, are of interest but the operators do not in themselves specify any procedures or algorithms for identifying the items of interest. Please see the link.
The main operations of relational algebra are 1. The select Operation 2. The projection operation 3. The union operation 4.The set different operations 5.The Cartesian-product operation. 6.The rename operation. 7.Additional operations. 8.The Set-Intersection operations. 9.Natural-join operations. 10.Division operation. 11.The Assignment operation.