arangosh> db.ids.ensureUniqueSkiplist("myId"); { "id" : "ids/1117182407", "type" : "skiplist", "fields" : [ "myId" ], "unique" : true, "sparse" : false, "isNewlyCreated" : true, "code" : 201 } arangosh> db.ids.save({ "myId": 123 }); { "_id" : "ids/1117444551", "_rev" : "1117444551", "_key" : "1117444551" } arangosh> db.ids.save({ "myId": 456 }); { "_id" : "ids/1117641159", "_rev" : "1117641159", "_key" : "1117641159" } arangosh> db.ids.save({ "myId": 789 }); { "_id" : "ids/1117837767", "_rev" : "1117837767", "_key" : "1117837767" } arangosh> db.ids.save({ "myId": 123 }); [ArangoError 1210: cannot create document, unique constraint violated]