xib

-- Based on the original articel at http://www.codeproject.com/Articles/22824/A-Model-to-Represent-Directed-Acyclic-Graphs-DAG-o
-- Here is a port to MySQL

-- Edge table
DROP TABLE IF EXISTS `Edge`;
CREATE TABLE IF NOT EXISTS `Edge` (
  `id` int(11) NOT NULL,
  `entry_edge_id` int(11) DEFAULT NULL COMMENT 'The ID of the incoming edge to the start vertex that is the creation reason for this implied edge; direct edges contain the same value as the Id column',
  `direct_edge_id` int(11) DEFAULT NULL COMMENT 'The ID of the direct edge that caused the creation of this implied edge; direct edges contain the same value as the Id column',
  `exit_edge_id` int(11) DEFAULT NULL COMMENT 'The ID of the outgoing edge from the end vertex that is the creation reason for this implied edge; direct edges contain the same value as the Id column',