2. The method according to claim 1 , further comprising: generating a base path starting from a named individual and ending at a canonical individual according to said original data and said converted explicit data; determining whether said query has a fork; and rewriting said query by appending a first query condition if said query has said fork and a root variable of said fork is matched with said canonical individual according to said original data and said converted explicit data, wherein said first query condition is an existing base path is required such that all matching variables in said fork are nodes directly or indirectly located in said base path.
3. The method according to claim 2 , further comprising: identifying said fork in said query according to a fork traversing principle, wherein said identifying step is performed for a root node in said query.