Abstract
We present Linkage Query Writer (LinQuer), a system for generating SQL queries for semantic link discovery over re-lational data. The LinQuer framework consists of (a) LinQL, a language for specification of linkage requirements; (b) a web interface and an API for translating LinQL queries to standard SQL queries; (c) an interface that assists users in writing LinQL queries. We discuss the challenges involved in the design and implementation of a declarative and easy to use framework for discovering links between different data items in a single data source or across different data sources. We demonstrate different steps of the linkage requirements specification and discovery process in several real world sce-narios and show how the LinQuer system can be used to create high-quality linked data sources. © 2009 VLDB Endowment.