In this paper a video data model that allows efficient and effective representation and querying of spatio-temporal properties of objects is presented. The data model is focused on the semantic content of video streams. Objects, events, activities performed by objects are main interests of the model. The model supports fuzzy spatial queries including querying spatial relationships between objects and querying the trajectories of objects. The model is flexible enough to define new spatial relationship types between objects without changing the basic data model. A prototype of the proposed model has been implemented. The prototype allows various spatio-temporal queries along with the fuzzy ones and it is prone to implement compound queries without major changes in the data model.