NoSQL / RDBMS hybrid with referential integrity (delete cascade)?

Question

Is there a database out there that gives you the benefit of referential integrity and being able to use a SQL type language for querying, but also lets entities be loosely defin

Answer 1

There's the Gremlin language, supported by the Neo4j graph database. Regarding your example, have a look at Access control lists the graph database way and here. There's also a web-based tool including a REST API to Neo4j and a Gremlin console, see neo4j/webadmin.