Systems and Methods to Query and Visualize Data and Relationships

A method constructs data visualizations. The method receives a visual specification, which includes properties and corresponding user-selected property values. The visual specification defines a data visualization layout. One property value identifies source databases for the data visualization. The method constructs node queries from the visual specification corresponding to one or more data fields in the source databases. The method also constructs link queries from the visual specification corresponding to a relationship between rows of the source databases. The method retrieves node tuples from the database that satisfy at least one of the node queries and retrieves link tuples from the database that satisfy at least one of the link queries. The method displays visual marks corresponding to the retrieved node tuples and displays edge marks in the corresponding to the retrieved link tuples. Each edge mark visually connects a pair of visual marks corresponding to the node tuples.