As I mentioned last week, Tiziana Catarci, Maria F. Costabile, Stefano Levialdi and Carlo Batini did a lot of work on the area of visual query systems. They were mainly interested in the task of writing queries using visual systems, but their research has a lot in common with my thesis project. Though I cannot write a précis for each of the papers, I will mention some details before including today’s précis.
Let’s start with the paper that provided the big picture about their research: What happened when database researchers met usability? wrote by Tiziana Catarci in 2000. It is interesting to note that at the beginning of their Ph.D. they intended to use entity-relationship diagrams as a database query interface which was the origin behind Query by Diagram (QBD or QBD*). This brought me back to the initials ideas about my thesis project. At that point the authors focused on the kinds of queries that the system will be able to express, but later on they conducted empirical studies to compare users’ performance while writing queries in SQL, QBD* and QBI. Next week’s précis — which will be the last one mandatory for the scientific writing course — will cover the comparison between QBD and QBI (a diagrammatic vs. an iconic system).
Today I will be looking at a taxonomy published by these authors in 1992. I am planning to finish reading a longer paper published by them in 1997 that also covers the classification of visual query systems. It is important to note that not only the papers are relevant to my research, but also the references provided in them. Without any more introduction, here is today’s précis:
Batini, C., Catarci, T., Costabile, M. F., and Levialdi, S.: Visual Query Systems: A Taxonomy. In Proceedings of the IFIP TC2/WG 2.6 Second Working Conference on Visual Database Systems II. E. Knuth and L. M. Wegner, Eds. IFIP Transactions, vol. A-7. North-Holland Publishing Co., Amsterdam, The Netherlands, pages 153-168 (1992).
Query systems make possible the representation of data models and requests. There is a clear division between query systems which use programming-like languages and those that utilize visual representations. The authors propose a taxonomy of visual query systems that will serve to analyze the influence of its features on HCI. The taxonomy is based on the operators available in the query language, notations, and classes of users.
According to their notation, visual query systems are classified as tabular, diagrammatic, iconic, or hybrid. Tabular representations are used by QBE, ESCHER, R2 and EMBS to display queries in 2D. The diagrammatic approach usually expresses the database schema through geometrical figures and connections, and the queries are represented by the selection of relevant elements and connections. The authors present QBD* as an example of system which uses this kind of diagram. The use of icons in query systems is illustrated with the description of ICONICBROWSER. A relevant aspect of these iconic systems is that the data model is not explicit. The authors also describe SICON, which is a hybrid system combining both diagrams and icons. Unfortunately, the figures with examples from these languages are not visible in the digital version of the paper.
Categories related to the availability of query operators and the classes of users are also discussed. However, the relationship between these categories and the examples of existing query systems is not analyzed in detail.