A Survey on Accessing Dataspaces

Dataspaces provide a co-existence approach for heterogeneous data. Relationships among these heterogeneous data are often incrementally identified, such as object associations or attribute synonyms. With the different degree of relationships recognized, various query answers may be obtained. In this paper, we review the major techniques for processing and optimizing queries in dataspaces, according to their different abilities of handling relationships, including 1) simple search query without considering relationships, 2) association query over object associations, 3) heterogeneity query with attribute correspondences, and 4) similarity query for similar objects. Techniques such as indexing, query rewriting, expansion, and semantic query optimization are discussed for these query types. Finally, we highlight possible directions in accessing dataspaces.