Proceedings of the 35th SIGMOD international conference on Management of data - SIGMOD '09
Schema evolution poses serious challenges in historical data management. Traditionally historical data have been archived either by (i) migrating them into the current schema version, providing an easy query interface, but compromising archival quality, or (ii) by maintaining them under the original schema version in which they first appeared, leading to a perfect archival quality, but also to a difficult query interface. In PRIMA system, we achieve the best of both approaches, by archiving
... orical data under the original schema version, while automatically adapting the user temporal queries to the relevant schema versions. The users are allowed to query the archive under a schema version of choice, letting the system to rewrite the queries to the (potentially many) involved schema versions in the past. Moreover, the system offers automatic documentation of the schema history, and allows to pose temporal queries over the metadata history itself. The proposed demonstration, highlights the system features exploiting both a syntheticeducational running example and the real-life evolution histories (schemas and data), which include hundreds of schema versions from Wikipedia and Ensembl. The demonstration offers a thorough walk-through of the system features and a hands-on system testing phase, where the audiences are invited to directly interact with the advanced query interface of PRIMA . The SIGMOD attendees will freely pose complex temporal queries over transaction-time databases subject to schema evolution, observing PRIMA's query rewriting and execution capabilities.