title: Hierarchical Data Models: Adjacency List vs. Nested Sets
body: <p>I have a product catalog. Each category consists of different number (in deep) of subcategories. The number of levels (deep) is unknown, but I quite sure that it will not be exceed of 5,6 levels. The data changes are much more rarely then reads.</p>
  
  <p>The question is: what type of hierarchical data model is more suitable for such situation. The project is based on Django framework and it's peculiarities (admin i-face, models handling...) should be considered.</p>
  
  <p>Many thanks!</p>