Implementing Cooperative Query Answering for Conjunctive Queries by Iterative Generalization

This webpage presents the outcome of a research project on Cooperative Query Answering developed at Inoue Laboratory at the National Institute of Informatics (Tokyo) with funding of the German Academic Exchange Service (DAAD).

When a user sends a query to a database system, the database might not be able to answer this query in a satisfactory manner. In particular, if the database system cannot find any answer to this query, the query is said to be a failing query. In a traditional database system, the user is left without an answer and is required to reformulate his query and resend the modified query to get some information from the database. In contrast, a cooperative database system automatically searches for informative answers: it offers the user information that is deemed to be close to what the user intended.

Here we present the CoopQA system that applies generalization operators to conjunctive queries; this results in a set of logically more general queries which might have more answers than the original query. CoopQA applies the following three operators to a conjunctive query:

These operators can be applied iteratively and it is sufficient to apply these three operators in a certain order: starting with GR applications, followed by DC applications and ending with AI applications. When searching for informative answers for a given query, this order is employed by the CoopQA system when applying the three operators iteratively in a tree-like structure.

Access and try out the CoopQA system by clicking here

Contact: Dr. Lena Wiese