Report generation is arguably the most important task for database applications. It is especially important for e-commerce applications, since dynamic Web pages consisting of database reports are essential to almost every transaction. When a report is generated, the layout of the data sources must be converted to the layout of the report. This conversion is called data transformation. It has been shown that data transformation can be simplified by using table operations. In this paper, we propose a set of new extendable table operations. We show that these operations can be applied visually so as to support visual programming for data transformation. We also implement a visual application called table presentation system (TPS) to demonstrate how these operations are used. With the aid of TPS, one can create sophisticated database reports without writing data transformation programs. Therefore the complexity of data transformation is greatly reduced.