By combining different forms of storage, we can define very complex data structures which combine the advantages of different storage schemas. The most obvious of these is <i>indexing</i>, for instance using a flat file to keep track of all the files in a directory. This sort of thing is supported in various ways in the wftk.

In addition, using the SQL engine in SQL::Statement means that we can combine data from lists in very useful ways on the fly. This section will contain some examples and serve to test the interface to SQL::Statement.