1. A graph database apparatus, comprising: a database interface that connects the graph database apparatus to a communication network; and a data storage medium comprising a plurality of data elements stored therein, the plurality of data elements comprising an attribute tree comprising a plurality of nodes and at least one relationship defined between the plurality of nodes, wherein the plurality of nodes comprise nodes for a plurality of resources, wherein the plurality of resources comprise resources of a contact center, a work item, and a workflow task, and the at least one relationship enables a work assignment engine to traverse the nodes of the attribute tree when making a work assignment decision, wherein every data element in the graph database apparatus is directly linked to every one of its adjacent data elements.