25. The computer program product according to claim 23 , wherein said computer program code for converting further comprises computer program code for generating a node table with one record for each said node, each said record of said node table including a field containing the value of said unique node identifier allocated to said node.
26. The computer program product according to claim 25 , wherein each record of said node table further comprises a field for at least one simple property of the corresponding node, a simple property being capable of taking at most one value per node.