Relational transducers for electronic commerce

Electronic commerce is emerging as one of the major Web-supported applicati ons requiring database support. We introduce and study high-level declarati ve specifications of business models, using an approach in the spirit of ac tive databases. More precisely, business models are specified as relational transducers that map sequences of input relations into sequences of output relations. The semantically meaningful trace of an input-output exchange i s kept as a sequence of log relations. We consider problems motivated by el ectronic commerce applications, such as log validation, verifying temporal properties of transducers. and comparing two relational transducers. Positi ve results are obtained for a restricted class of relational transducers ca lled Spocus transducers (for semi-positive outputs and cumulative state). W e argue that despite the restrictions, these capture a wide range of practi cally significant business models. (C) 2000 Academic Press.