Abstract: A mechanism for rewriting a bounded query onto a view is disclosed. A query, access constraints, and cached view(s) are obtained. The cached view(s) contain results of the query as applied to a dataset stored in a database. A query rewriting plan is generated by adding a fetch from query operation to the plan when a rewritten query variable can be fetched from a query constant. A fetch from database operation is added to the plan when a rewritten query variable can be fetched as a query variable that obtains bounded data from the database. An access view operation is added to the plan when a rewritten query variable can be fetched from the cached view. The query rewriting plan is executed to fetch retrieved data. The query is executed on the retrieved data to determine updated results to the query without reapplying the query to the dataset.

Abstract: A mechanism for rewriting a bounded query onto a view is disclosed. A query, access constraints, and cached view(s) are obtained. The cached view(s) contain results of the query as applied to a dataset stored in a database. A query rewriting plan is generated by adding a fetch from query operation to the plan when a rewritten query variable can be fetched from a query constant. A fetch from database operation is added to the plan when a rewritten query variable can be fetched as a query variable that obtains bounded data from the database. An access view operation is added to the plan when a rewritten query variable can be fetched from the cached view. The query rewriting plan is executed to fetch retrieved data. The query is executed on the retrieved data to determine updated results to the query without reapplying the query to the dataset.

Abstract: A processor executes instructions stored in non-transitory memory to determine whether a query to big data is bounded evaluable, or may be rewritten to access a bounded amount of data or information in a dataset. A query plan may retrieve the information by using indices in access constraints of the query. The cost associated with obtaining the information by using the query plan may be dependent on the query and access constraints and not the size of the dataset. A query plan to obtain the information may be formed for different types or classes of queries, such as conjunctive queries (CQ), unions of conjunctive queries (UCQ) and positive existential FO (first order) conjunctive queries (?FO+). When a query is not bounded evaluable, a determination is made whether an approximation to the information may be retrieved. An approximation may be obtained by using upper and lower envelopes or specialized queries.

Abstract: Methods and apparatus are provided for detecting data inconsistencies. Methods are disclosed for determining whether a set of conditional functional dependencies are consistent; determining a minimal cover of a set of conditional functional dependencies and detecting a violation of one or more conditional functional dependencies in a set of conditional functional dependencies. The conditional functional dependencies comprise one or more constraints that data in a database must satisfy including at least one pattern with data values.

Abstract: Methods and apparatus are provided for detecting data inconsistencies. Methods are disclosed for determining whether a set of conditional functional dependencies are consistent; determining a minimal cover of a set of conditional functional dependencies and detecting a violation of one or more conditional functional dependencies in a set of conditional functional dependencies. The conditional functional dependencies comprise one or more constraints that data in a database must satisfy including at least one pattern with data values.

Abstract: Methods and apparatus are provided for rewriting view queries into equivalent queries on the source document. According to one aspect of the invention, methods are provided for processing a view query on a database view. The method comprises the steps of translating the view query to a mixed finite state automata representation of a document query on one or more documents underlying the database view; and evaluating the document query on the one or more documents to obtain a result to the view query. The view query may be, for example, a regular XPath query.