  Graph databases have emerged as the fundamental technology underpinning
trendy application domains where traditional databases are not well-equipped to
handle complex graph data. However, current graph databases support basic graph
structures and integrity constraints with no standard algebra. In this paper,
we introduce GRAD, a native and generic graph database model. GRAD goes beyond
traditional graph database models, which support simple graph structures and
constraints. Instead, GRAD presents a complete graph database model supporting
advanced graph structures, a set of well-defined constraints over these
structures and a powerful graph analysis-oriented algebra.
