arangosh> a1 = db.example.insert({ a : 1 });
{
"_id" : "example/1148690988",
"_rev" : "1148690988",
"_key" : "1148690988"
}
arangosh> a2 = db._update(a1, { b : 2 });
{
"_id" : "example/1148690988",
"_rev" : "1149018668",
"_key" : "1148690988"
}
arangosh> a3 = db._update(a1, { c : 3 });
[ArangoError 1200: precondition failed]