1. A method of matching a first entity to a second entity by evaluating Boolean expressions, the method comprising: identifying a set of criteria vertices for a second entity vertex by traversing a graph database in a manner constrained to fact vertices identified for the second entity, wherein the graph database relates fact vertices to the criteria vertices by edges corresponding to Boolean expressions for satisfying criteria for matching first entities to second entities; selecting one of the first entities based on the criteria vertices of the set; and matching the first entity to the second entity based on the selection.