Module: Sequel::Plugins::Tree::ClassMethods

Defined in:

lib/sequel/plugins/tree.rb

Instance Attribute Summary (collapse)

• - (Object) parent_column

  The symbol for the column containing the value pointing to the parent of the leaf.

• - (Object) tree_order

  The column symbol or array of column symbols on which to order the tree.

Instance Method Summary (collapse)

• - (Object) inherited(subclass)

  Copy the parent_column and order_column to the subclass.

• - (Object) roots

  Returns list of all root nodes (those with no parent nodes).

• - (Object) roots_dataset

  Returns the dataset for retrieval of all root nodes.

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# File 'lib/sequel/plugins/tree.rb', line 56

def parent_column
  @parent_column
end

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# File 'lib/sequel/plugins/tree.rb', line 52

def tree_order
  @tree_order
end

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# File 'lib/sequel/plugins/tree.rb', line 59

def inherited(subclass)
  super
  subclass.parent_column = parent_column
  subclass.tree_order = tree_order 
end

TreeClass.roots # => [root1, root2]

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# File 'lib/sequel/plugins/tree.rb', line 68

def roots
  roots_dataset.all
end

TreeClass.roots_dataset => Sequel#Dataset

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# 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