Abstract: A method and a system manage the execution of a production order via a MES system. Pieces of equipment and their connections as nodes and arcs of a digraph are associated for reproducing a layout of a plant where the production has to be made. The data of the layout are stored as tables of the nodes and arcs. At least one virtual line is created starting from a node selected as a root node and including a plurality of nodes reachable from the root node, the at least one virtual line lying over the plant layout. The data of the at least one virtual line is stored as tables of nodes and arcs of a sub-digraph representing the virtual line.