We have designed a high-level SQL-like language called W3QL to support effective and flexible query processing, which addresses the structure and content of WWW nodes and their varied sorts of data.
W3QS is an operational prototype system that executes W3QL queries.
This article formally defines the syntax and semantics of W3QL. As an important by-product, we provide a formal definition of the WWW itself.
Section 2 presents motivation and W3QL query examples.
W3QL allows the definition of complex WWW queries and W3QS automates the information extraction.
Such a hypertext path is expressed in W3QL by the expression: n1,l1,(n2,l2),l3,n3.
W3QL allows the mapping of specific pages to a node variable.
W3QL allows the use of external programs to analyze file contents.
At first glance, the syntax of W3QL might seem complex.
In W3QL, forms and their answers are considered linked by hypertext links.
We now define the formal syntax and semantics of W3QL. This is done in two stages: we define a formal model of WWW resident information and then the syntax and semantics of W3QL are defined within this model.