Fig. 5
From: HyGraph: a subgraph isomorphism algorithm for efficiently querying big graph databases
An example for a complex query: “Find the families consisting of a man, a wife, at least two children, one from an ex-wife, who live at the same address in Population Database”. The relationship “S” stands for “spouse of”, “O_S” stands for “old spouse of”, “M” stands for “has mother”, “F” stands for “has father” and “L_I” stands for “lives in”