Motivation background Data integration is a pervasive challenge faced in applications that need to query across multiple autonomous and heterogeneous data sources Data integration is crucial in large enterprises that own a multitude of data sources a For better cooperation among agencies, each with their own data sourcesMotivation & Background ◼ Data integration is a pervasive challenge faced in applications that need to query across multiple autonomous and heterogeneous data sources. ◼ Data integration is crucial in large enterprises that own a multitude of data sources. ◼ For better cooperation among agencies, each with their own data sources