One of the most typical data structures to use in any web application is a tree.
You may be creating an e-commerce application and you need to organise your products in categories. Or you may be programming a news web application and need to organise your posts in breadcrumbs. You need a tree.
Sergio del Amo, curator of the newsletter Groovy Calamari, illustrates how to map a tree with GORM and SQL using an Adjacency List, a Path Enumeration, Nested Sets or Closure Tables. We will evaluate how each solution performs in terms of ease of child querying, tree querying, insertion, deletion or referencial integrity.
If you ever need to map a tree in a relation database you will learn something valuable in this talk.