Grammars++ for modelling information in text

Grammars provide a convenient means to describe the set of valid instances in a text database. Flexibility in choosing a grammar can be exploited to p rovide information modelling capability by designing productions in the gra mmar to represent entities and relationships of interest to database applic ations. Additional constraints can be specified by attaching predicates to selected non-terminals in the grammar. When used for database definition, g rammars can provide the functionality that users have come to expect of dat abase schemas. Extended grammars can also be used to specify database manip ulation, including query, update, view definition, and index specification. (C)1999 Elsevier Science Ltd. All rights reserved.