Uninformed: Informative Information for the Uninformed

Vol 8» 2007.Sep

Data Type Tier

The data type tier uses the set of data flow paths found at the module tier to construct a data flow graph that shows the data flow relationships between formal input and formal output parameters passed between data types. The graph is generated using the one-to-many table that was populated during generalization which conveys the data type data flow paths that were generalized by the set of qualified module data flow paths. The graph that is generated as a result is shown in figure 16.

Figure 16: Data type tier data flow graph for the web application representing potentially reachable paths between the source and sink flow descriptor. These paths were qualified by reachable paths found at the module tier.
Image expath-datatype

Using the graph, the $ Reachability()$ algorithm is again employed to find paths between the source and sink flow descriptor at the data type tier. Due to the simplicity of the example application, only a few data flow paths were rendered. The complete data flow path from fout(System.Web.HttpRequest) to fin(System.Diagnostics.Process.Start) can be clearly seen.