This study compares a linear keyword language interface and a restricted natural language interface for data retrieval by a novice user. The comparison focuses on the effect of different data base interfaces on user performance (as measured by query correctness and query writing time) in a query writing task across varying query types and training levels. To accomplish this objective, a laboratory experiment was conducted using a split-plot factorial design using two between-subjects factors and one within-subjects factor. The results indicate that the restricted natural language subjects performed significantly better than the linear keyword language subjects in terms of both query correctness and query writing time.