1. Method of generating reference patterns able to represent hierarchized data, the hierarchized data being structured in accordance with a schema, the hierarchized data being organized in a plurality of items, characterized in that it comprises the following steps: extracting primary structural patterns from the schema, each of the primary structural patterns representing a set of structural information; associating items in the plurality of items with at least one primary structural pattern extracted; grouping the associated items according to a predetermined criterion; and determining one reference pattern per group of items from associated primary structural patterns; the said reference pattern comprising at least one piece of structural information able to represent at least one piece of structural information of each item of the group that is associated with it.