arangosh> db._create("users", { keyOptions: { allowUserKeys: false } }); [ArangoCollection 15294, "users" (type document, status loaded)] arangosh> db.users.save({ name: "user 1" }); { "_id" : "users/15298", "_key" : "15298", "_rev" : "_WpTB_Dy--_" } arangosh> db.users.save({ name: "user 2", _key: "myuser" }); [ArangoError 1222: unexpected document key] arangosh> db.users.save({ name: "user 3" }); { "_id" : "users/15303", "_key" : "15303", "_rev" : "_WpTB_D2--A" }