This report describes the design, functionality, and implementation of a data flow query language (DFQL), that visually represents a query as a directed acyclic data flow graph. The language is well suited for application domains such as scientific databases, where data analysis and visualization need to be tightly coupled with data retrieval, and the relationships between the entities are ill-defined. Unlike most visual query languages that are declarative, DFQL is a functional language and thus provides the ability to combine data retrieval, analysis, and visualization, intuitively in a single query.
