US Patent 9633076 Blending and visualizing data from multiple data sources

A method dynamically combines data from multiple data sources. A visual specification for a data visualization requires data from a primary data source and one or more secondary data sources. The primary data source is independent of the secondary data sources. The visual specification includes a first set of dimension fields that specify a hierarchical level for the data visualization. A second set of dimension fields specify a hierarchical level for joining data sets from the data sources. The hierarchical level for joining data sets is more granular than the hierarchical level for the data visualization. For each data source, a query is generated, and a data set is retrieved from the data source using the query. A single combined data set is formed that includes the dimension fields in the first set. The combined data set is rolled-up and a data visualization is displayed using the rolled-up data.