Method and data access unit for storage of data records for creating a serialized charging record formatted for insertion into a charging database. The method includes traversing the hierarchical charging record and for each part node of said hierarchical charging record identifying an attribute of the part node and determining if said attribute is a key attribute or a search attribute and if affirmative storing an attribute value of said attribute in a field of the serialized charging record based on a charging database configuration definition. A part segment comprising the attribute value and a data value token is stored in a payload body field of the serialized charging record with a part node indicator representing the location of the part node in the hierarchical charging record based on a hierarchical charging record configuration definition. A method and data access unit for creating a hierarchical charging record is also disclosed. An advantage is that a serialized charging record may be stored in one storage entity such as a table row.