 Here we present Sigma Worksheet, a new system for interactively constructing data warehouse queries through visual direct manipulation. Sigma Worksheet enables users to perform powerful interactive ad-hoc visual data analysis without writing queries.
<clarity>  Here we present Sigma Worksheet, a new system for interactively constructing data warehouse queries through visual direct manipulation. Sigma Worksheet enables users to perform powerful interactive ad-hoc visual data analysis without writing queries.
 Here we present Sigma Worksheet, a new interactive system that enables users to perform powerful interactive ad-hoc visual data analysis without writing queries.