Visual Query Systems

1566 Words7 Pages
subsubsection{Comparison Strategy 2} Not only can we compare these several visual query systems from the perspective of querying process, we may also look at them in view of their usability, i.e. how much can be done with the system? Can the underlying visual query language represent recursive /nested queries? Can the underlying visual query language supported by a system represent queries with negation? Figure~ ef{fig:strategy2} answers these questions by showing the usability of each visual query system. egin{figure} centering includegraphics{background/image/table2} caption{Overview of visual query systems with regards to their usability label{fig:strategy2}} end{figure} subsection{The Graphlog Language} The language is suitable for querying and visualizing structural data. Graphlog~cite{graphlog:consens} and Hy+ are developed in University of Toronto under the leader of Mariano P. Consens. Graphlog is the language to support visualizing queries and Hy+ is the system for using Graphlog to pose queries. From the view of posing queries for retrieving data, different degrees of visualization are involved in Structural Query Language(SQL) queries, form-based queries, and graph-looking queries such as in Computer-Aided-Design(CAD). At the current stage, the most scientist-friendly is the graph-looking query environment. Among other researches, the database query language Graphlog and Hy+ query system gives an successful example. The Hy+ system is implemented using the Object-Oriented language Smalltalk. %A hygraph is a hybrid between Harel’s higraph~cite{harel:visual} and directed hypergraphs~cite{berge} (and hence the name); it extends the notion of a graph by incorporating blobs in addition t... ... middle of paper ... ...ore information and is not abstract as compared to textual displays. Especially when the size of the data set is large, data visualization is a must for people to better understand complex structure of the data, the embedded information beneath the data so as to make better decisions and to discover information that might otherwise remain unknown. A survey about various data visualization approaches and visualization techniques can be found in~cite{herman}. Data visualization has been researched for decades. What we are interested here are the techniques which visualize abstract data such as an object and the relationships among objects, instead of real work object 2D or 3D rendering. The graph visualization techniques is worth learning as the visual query system we are aiming to build is going to visualize the query result, which is abstract data.

More about Visual Query Systems

Open Document