Listing 1: Code That Creates and Populates the Links Table
USE tempdb;
SET NOCOUNT ON;
GO
IF OBJECT_ID('Links') IS NOT NULL
  DROP TABLE Links;
GO

CREATE TABLE Links
(  src_pid int NOT NULL,
  tgt_pid int NOT NULL,
  PRIMARY KEY(src_pid, tgt_pid) );
GO
INSERT INTO Links(src_pid, tgt_pid) VALUES(1, 2);
INSERT INTO Links(src_pid, tgt_pid) VALUES(1, 3);
INSERT INTO Links(src_pid, tgt_pid) VALUES(1, 4);
INSERT INTO Links(src_pid, tgt_pid) VALUES(1, 7);
INSERT INTO Links(src_pid, tgt_pid) VALUES(2, 5);
INSERT INTO Links(src_pid, tgt_pid) VALUES(2, 6);
INSERT INTO Links(src_pid, tgt_pid) VALUES(4, 7);
INSERT INTO Links(src_pid, tgt_pid) VALUES(7, 8);
GO