The symbol for the column containing the value pointing to the parent of the leaf.
The column symbol or array of column symbols on which to order the tree.
Returns list of all root nodes (those with no parent nodes).
TreeClass.roots # => [root1, root2]
# File lib/sequel/plugins/tree.rb, line 63 def roots roots_dataset.all end
Returns the dataset for retrieval of all root nodes
TreeClass.roots_dataset => Sequel#Dataset
# File lib/sequel/plugins/tree.rb, line 70 def roots_dataset ds = filter(parent_column => nil) ds = ds.order(*tree_order) if tree_order ds end