A method and system for storing and retrieving a packaging hierarchy of traceable physical items includes at an item marking location, marking physical items to be packaged in the packaging hierarchy, with a unique code with a first and second identifier, transferring packaging relationships between the codes to a track and trace system, identifying for each code in the packaging relationships, hierarchical code relations expressed as parent and/or child codes, and for each code, storing the hierarchical code relations in a section of a data storage location of the first computer system, wherein a start position of the section is determined by a combination of the first and second identifiers of the code.