The problem motivating this study is that database query facilities are not effectively meeting the needs of casual users. A solution to this problem is especially important due to the increasing number of potential casual users. There is considerable controversy revolving around the question of which elements and/or which combination of elements within the casual users' environment are necessary to provide an effective man/machine interface. The purpose of the study is to extend the basic knowledge relating to the effect of using different data models, the effect of cognitive style differences, and the interaction effects of these two independent variables on casual users' performance and confidence in writing database queries. The data models being investigated are the relational, hierarchical, and network models. The cognitive style classifications used are two of the Jungian dimensions, Sensing/Intuition and Thinking/Feeling.