Method of hierarchical searching on a conditional graph

A method of hierarchical searching for data satisfying at least one set of predetermined criteria C, in a directed acyclic graph comprising nodes and links between said nodes and which is stored in tables of a relational database management system able to be interrogated by a query language, the criteria being determined on the nodes and/or the links, wherein each criterion being determined

• blocking, such that as soon as the criterion is not satisfied on a link or a node, the terminal node of this link respectively this node and its descendant nodes are excluded,
• or non-blocking such that as soon as the criterion is not satisfied on a link respectively a node, only this link respectively this node is excluded, without consequence to its descendant nodes,
• wherein said method comprises the following steps:
• separating the set C into a set of blocking criteria Cb and a set of non-blocking criteria Cnb;
• searching of with the query language for the nodes of the graph satisfying the set of blocking criteria Cb, these nodes being grouped together in a set G, and
• searching with the query language, for the nodes of G satisfying the set of non-blocking criteria Cnb.