In this work, we propose an optimized data assignment algorithm for time dependent non-replicated distributed database systems based on a modified Dijkstra shortest path algorithm findings. Fragment assignment is determined from the access cost matrix and a threshold value obtained from the query matrix and site access record. Transmission, storage and computational overhead costs are computed and compared with existing algorithms. This model uses fragment preferred site technique to ensure nonreplication at sites and to avoid constraints violation if fragment replication occurs. The algorithm is demonstrated through detailed example and proved robust in terms of transmission cost while it lags behind in terms of storage cost.