arangosh> a1 = db.example.insert({ a : 1 });
{
"_id" : "example/18389",
"_key" : "18389",
"_rev" : "_XGh_XW6--_"
}
arangosh> a2 = db._replace(a1, { a : 2 });
{
"_id" : "example/18389",
"_key" : "18389",
"_rev" : "_XGh_XX---_",
"_oldRev" : "_XGh_XW6--_"
}
arangosh> a3 = db._replace(a1, { a : 3 });
[ArangoError 1200: precondition failed]