Comment 1 for bug 627732

The data to be exported is provided by db.DatabaseAdapter.getAllCategoriesMap(), which gathers the categories from the database and creates according objects. However, the database does not include direct information about a parent of a category, thus the parent field is always null.
The required information about the hierarchy of the categories can be extracted from the left/right properties of a category, like done in getAllCategoriesTree() via CategoryTree.createFromCursor(). This mechanism obviously needs to be adopted.