Us-sql: Managing uncertain schemata

In this paper we describe a demo concerning the management of uncertain schemata. Many works have studied the problem of representing uncertainty on attribute values or tuples, like the fact that a value is 10 with probability .3 or 20 with probability .7, leading to the implementation of probabilistic database management systems. In our demo we deal with the representation of uncertainty about the meta-data, i.e., about the meaning of these values. Us- ing our system it is possible to create alternative proba- bilistic schemata on a database, execute queries over uncertain schemata and verify how this additional information is stored in an underlying relational database and how queries are executed.