arangosh> a1 = db.example.insert({"a" : 1}); { "_id" : "example/1131944658", "_rev" : "1131944658", "_key" : "1131944658" } arangosh> a2 = db.example.update(a1, {"b" : 2, "c" : 3}); { "_id" : "example/1131944658", "_rev" : "1132337874", "_key" : "1131944658" } arangosh> a3 = db.example.update(a1, {"d" : 4}); [ArangoError 1200: precondition failed] arangosh> a4 = db.example.update(a2, {"e" : 5, "f" : 6 }); { "_id" : "example/1131944658", "_rev" : "1132993234", "_key" : "1131944658" } arangosh> db.example.document(a4); { "a" : 1, "b" : 2, "c" : 3, "e" : 5, "f" : 6, "_id" : "example/1131944658", "_rev" : "1132993234", "_key" : "1131944658" } arangosh> a5 = db.example.update(a4, {"a" : 1, c : 9, e : 42 }); { "_id" : "example/1131944658", "_rev" : "1133255378", "_key" : "1131944658" } arangosh> db.example.document(a5); { "a" : 1, "b" : 2, "c" : 9, "e" : 42, "f" : 6, "_id" : "example/1131944658", "_rev" : "1133255378", "_key" : "1131944658" }