This causes the following error message:
Msg 2627, Level 14, State 1, Line 14Violation of UNIQUE KEY constraint 'AKEdge'. Cannot insert duplicate key in object 'dbo.Edge'. The duplicate key value is (455672671, 0, 455672671, 1).
So what is this: (455672671, 0, 455672671, 1)?
Click through to understand what this all means. Louis also has a quick procedure which looks up those details.