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Quasi-inverses of schema mappings

... it is rare that a schema mapping possesses an inverse. In this paper, we introduce and study the notion of a quasi-inverse of a ... negative results about the existence of quasi-inverses. In particular, we show that every LAV (local-as-view) schema mapping has a ...

Publication - huliganka - 04/17/2013 - 02:49 - 0 comments - 1 attachment

Constraint-based XML query rewriting for data integration

... or XML schemas, and can be independently designed. In addition to the source-to-target mappings, we consider as part of the ... at the target. We define the semantics of query answering in such an integration scenario, and design two novel algorithms, basic query ...

Publication - huliganka - 04/17/2013 - 00:38 - 0 comments - 1 attachment

Nested Mappings: Schema Mapping Reloaded

... 666.47 KB Many problems in information integration rely on specifications, called schema mappings, that ... for both relational and nested data are well-known. In this work, we present a new formalism for schema mapping that extends these existing formalisms in two significant ways. First, our nested mappings allow for nesting and ...

Publication - huliganka - 04/17/2013 - 00:05 - 0 comments - 1 attachment

Query reformulation with constraints

... be a Σ1-query. An (equivalent) reformulation of q1 in the presence of C is a Σ2-query, q2, such that q2 gives the same ... ∪ Σ2-database instance that satisfies C. In general, there may exist multiple such reformulations and choosing among ...

Publication - huliganka - 04/16/2013 - 23:38 - 0 comments - 1 attachment

Clio Grows Up: From Research Prototype to Industrial Tool

... for expressing declarative schema mappings, has progressed in the past few years from a research prototype into a technology that is ... depending on the kind of schemas and systems involved in the mapping. Clio currently produces XQuery, XSLT, SQL, and SQL/XML queries. ...

Publication - admin - 04/16/2013 - 13:38 - 0 comments - 1 attachment

Mapping Adaptation under Evolving Schemas

... to translate data from one representation to another. In dynamic environments like the Web, data sources may change not only ... query capabilities. Such changes must be reflected in the mappings. Mappings left inconsistent by a schema change have to be ...

Publication - cat - 04/16/2013 - 10:49 - 0 comments - 1 attachment

Semantic Adaptation of Schema Mappings when Schemas Evolve

... Schemas evolve over time to accommodate the changes in the information they represent. Such evolution causes invalidation of ... depending on the schemas, such as schema mappings. In a heterogenous environment, where cooperation among data sources depends ...

Publication - cat - 04/16/2013 - 09:16 - 0 comments - 1 attachment