Modern search engines answer keyword-based queries extremely efficiently. The
impressive speed is due to clever inverted index structures, caching, a domain-independent …

Query languages for graph databases started to be investigated some 25 years ago. With
much current data, such as linked data on the Web and social network data, being graph …

Publisher Summary This chapter describes XSEarch, a semantic search engine for XML.
XSEarch has a simple query language, suitable for a naive user. It returns semantically …

Database researchers have striven to improve the capability of a database in terms of both
performance and functionality. We assert that the usability of a database is as important as …

XKeyword provides efficient keyword proximity queries on large XML graph databases. A
query is simply a list of keywords and does not require any schema or query language …

For many problems arising in the setting of graph querying (such as finding semantic
associations in RDF graphs, exact and approximate pattern matching, sequence alignment …

Tree patterns are fundamental to querying tree-structured data like XML. Because of the
heterogeneity of XML data, it is often more appropriate to permit approximate query …

XML repositories are usually queried both on structure and content. Due to structural
heterogeneity of XML, queries are often interpreted approximately and their answers are …

We explore flexible querying of RDF data, with the aim of making it possible to return data
satisfying query conditions with varying degrees of exactness, and also to rank the results of …

The ability to compute top-k matches to XML queries is gaining importance due to the
increasing number of large XML repositories. The efficiency of top-k query evaluation relies …