two database hierarchy methods -

two database hierarchy methods -

i'm surprised searching hard because don't know term, , "database hierarchy" means else.

i familiar self-referencing hierarchy table each row has id field , parent_id field, row can have parent, creating "tree"

however know there method uses left , right fields , relative position left , right overall. have never used it's in codebase i'm working on. can give me links type of heirarchy structure? thanks

oops should have thought of this: search for:

left right hierarchy

that affords plethora of images, in add-on "nested set model" mentioned above. thanks!

database hierarchy