An automatic visual database interface
Etienne Pichat, Dib Saker · 1995
Today’s relational and object-oriented databases come with very powerful declarative query languages like SQL. However, such languages are still not adapted to the needs of the occasional user because of their syntax requirements and because they do not facilitate the understanding of the database semantics, navigation within tables and the formulation of queries. This paper proposes an especially assisting visual interface for database query. This is possible with a powerful and easy-to-understand database scheme representation, the normalized semantic graph (NSG) which is underlain by the Universal Relation with Inclusions (URI) data model, and by making NSG more explicit by automatic generation. First the interface displays the set of the relational schemes and a set of basic links in background: it is the relation-to-relation NSG , a kind of restriction of NSG. Displaying links with tables makes it easier for the user to understand the database scheme and to find his way about tables. Secondly the interface calculates and displays the possible join-links of a table designated by the user. This is the evolving query graph . As it evolves with the designated node, the user progressively specifies his query: he only has to select the attributes to project, precise selection conditions and click on the desired join-links to obtain the query graph , which is translated in SQL. This interface by-passes syntactic specifications and assists the user as closely as possible in his declaration. The paper also shows how to generate all the possible links between relations implied by the NSG as well as how to complete them with compatible attributes. In this way, the complete query graph is obtained. But to avoid drowning the user in a mass of information, only those links of the complete query graph which are contiguous to the node designated by the user are displayed. A prototype is available in the GraphTalk® environment.