arangosh> db._create("users", { keyOptions: { allowUserKeys: false } }); [ArangoCollection 107727, "users" (type document, status loaded)] arangosh> db.users.save({ name: "user 1" }); { "_id" : "users/107731", "_key" : "107731", "_rev" : "_XPb90cO--_" } arangosh> db.users.save({ name: "user 2", _key: "myuser" }); [ArangoError 1222: unexpected document key] arangosh> db.users.save({ name: "user 3" }); { "_id" : "users/107736", "_key" : "107736", "_rev" : "_XPb90cS--_" }