Most of the time, final users experiment difficulties when interacting with databases in order to obtain valuable information from them. Such difficulties are related to data representation and the complexity of the mechanisms usually used in the interaction. In this sense, Data Warehouse Schemas provide an interesting alternative to reduce the complexity and the number of relationships existing in the underlying model, facilitating the view and the interaction with the end-user. However, there are still some difficulties to solve regarding access and interaction with data models by non-experts in specific query languages.

Over the last years, there have been different types of visual tools and languages to assist non-expert users to build queries by interacting with visual representations of data models. However, many of these existing tools lack of expressiveness and/or ease of use. This lack of expressiveness sometimes implies that some of the capabilities to build more complex queries are overlooked, or they are not easily available for non-experts. In order to overcome these drawbacks, we provide a work intended to demonstrate that is possible to get a real trade-off between expressiveness and ease of use. This hypothesis has been backed up with a tool reducing the gentle slope of complexity in creating database queries. Such a tool, based on the End-User Development paradigm, is called VISQUE (VIsual Star-schema Query by Example), and it proposes the creation of queries focused on Data Warehouse, allowing non-experts database users to build queries in a visual way and with lower expressive limitations. To do so, we propose a visual language including different visualization techniques, enabling end-users to build complex queries that include set operations and sub-queries, which are issues not usually covered by related tools.