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.
Copy the parent_column
and order_column
to the
subclass.
# File lib/sequel/plugins/tree.rb, line 59 def inherited(subclass) super subclass.parent_column = parent_column subclass.tree_order = tree_order end
Returns list of all root nodes (those with no parent nodes).
TreeClass.roots # => [root1, root2]
# File lib/sequel/plugins/tree.rb, line 68 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 75 def roots_dataset ds = filter(parent_column => nil) ds = ds.order(*tree_order) if tree_order ds end