1. A Method carried out in a computer system, said system comprising: a spreadsheet file having at least a sheet with lines and columns, wherein columns represent fields, said sheet having: a header portion having at least a designation line with a field designation for each column, a data portion, wherein each line comprises a record a processing unit, a keyboard, a mouse, a display unit, the method comprising: /a/ identifying a single reference field, /b/ an allocating step in which a field type is allocated to fields other than the reference field, said field type belonging to a set of field type comprising attribute, parent/child, and flow, /c/ defining a link, for each designation field with an allocated type, which establishes a link with another linked field, within said sheet or another sheet, wherein: for a field type being attribute, said link is an attribute link and defines properties relative to the reference field or to a parent field, for a field type being parent/child, said link is a parent/child link and defines a membership relationship, wherein a child field belongs a parent field, for a field type being flow, said link is a flow link and defines a message relative to the reference field, /d/ building a hierarchical model representing the parent/child links, defining at least two hierarchical levels, said model comprising all the fields involved in the parent/child links, /f/ generating a graphical hierarchical multilevel representation of said sheet content, with at least one graphical view showing one or more hierarchical level and displaying said representation on the display unit.