The enhancements in multimedia technology have accelerated the development of new techniques for querying and retrieval in video databases. Based on these new techniques, effective user interfaces are designed especially for query specification. Since the Internet is a suitable multiple client environment, most of the video database systems are designed to work over the Internet. In this thesis, a web-based user interface for a video database system is presented. The interface is composed of a hierarchical windows-based structure where logically separable sub-queries are handled in separate windows. For example, spatial and motion queries are handled separately. The separation of the interface aims to facilitate the query specification process. Furthermore, the user is allowed to get partial results for the sub-queries. The retrieval and result presentation process displays the query results in the form of video frame sequences on a separate window with the capability of playing each result separately. As another contribution of this thesis, considering the fact that most of the systems include querying by object features, a novel approach for color and shape querying and retrieval is proposed. The proposed approach is histogram-based and it is shown through the performance experiments that it overcomes the deficiencies of the existing methods. This new approach is supported by an auxiliary object extraction tool in the query-by-feature sub-system of the video database system. The object extraction tool is semi-automatic, hence it can successfully capture salient object regions for most of the images and/or video frames.