15. A system, comprising: a processing module comprising a non-transitory computer readable medium storing instructions that, when executed, cause the system to: receive a first query that is associated with a first type of database; translate, using primitives, the first query into an edge query that is associated with a graph database storing a graph, wherein: the first type of database has a different data model than the graph database; the graph comprises nodes, edges between the nodes, and predicates to represent and store data with index-free adjacency; and the primitives include: a rule based on edges in the graph that expresses a relational schema in the first type of database, and information associated with a compound key that specifies a relationship between the nodes, the edges and the predicates in the graph corresponding to a table in the first type of database; execute the edge query against the graph database, wherein the edge query identifies an edge associated with a predicate that specifies one or more of the nodes in the graph; and receive a result in response to the edge query, wherein the result includes a subset of the graph.
18. The system of claim 15 , wherein the first query is compatible with a Structured Query Language.