Question

I want to have folders and documents which every one have a folder. Folders can have infinite children folders. What is the best mysql schema in your opinion.Do you think this is good?

Table Folders
  id
  name
  parent (if null the root)
  auth_user (access control type)
  created_date
  created_by

 Table documents
   id
   name
   type
   idFolder (FK id of folders)
   auth_user (access control type)
   created_date
   created_by

Do you think the above is good or gonna have problem later? Do you think with the above can get fast and easy the folders tree (i think with ORDER BY parent ASC can get the tree right)?

Answer 1

adjacency lists are nice for inserts and moving sub-trees but if you need to query deeper than one level it’s pain in the a** because you will end up with n-joins if you go n-levels deep. An example: Show me all descendants/ancestors of Folder X.

I suggest to use the adjacency list (the parent_id) in combination with one of the following models:

• Nested Sets

• Materialized Paths

I really like the nested set – but it has a draw back – inserts are slow. But usually you will have more reads (browsing) the structure than inserting new nodes.

Another thing:

I usually put folders and documents in the same table and flag them with a boolean is_folder column. I like to think of folders/files as “nodes” in a tree so they’re basically the same. Further metadata will be stored in another table.