Querying the SaintEtiQ Summaries - Dealing with Null Answers

The data summarization techniques are usually not provided with tools for endusers to efficiently use the produced summaries. In a previous work, a querying tool for the SaintEtiQ summarization model has been outlined. It takes advantage off the hierarchical structure of those summaries to efficiently describe tuples that satisfy some selection criteria. This querying mechanism can be seen both as a Boolean one over the summaries, and as a flexible one over the underlying relational tuples. This paper mainly investigates the case of null answers. It is shown how, in this case, alternative queries with non-null answers can be proposed to the user