There are two types of relational database manipulation language: procedural and assertional. A procedural language is one in which a query is expressed through a sequence of operations. This category ...

The paper proposes a method of parsing for relational algebra expressions, which is based on the use of reverse Polish notation (postfix notation). The operation algorithm of the shunting yard, ...

An extension of E.F. Codd's relational algebra (1970) with an alpha ( alpha ) operator is presented that allows a large class of natural and useful recursive queries to be expressed, and yet has the ...