arangosh> db.ids.ensureIndex({ type: "skiplist", fields: [ "name.first", "name.last" ], unique: true }); { "id" : "ids/1155799762", "type" : "skiplist", "fields" : [ "name.first", "name.last" ], "unique" : true, "sparse" : false, "isNewlyCreated" : true, "code" : 201 } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "hansen" }}); { "_id" : "ids/1156127442", "_rev" : "1156127442", "_key" : "1156127442" } arangosh> db.ids.save({ "name" : { "first" : "jens", "last": "jensen" }}); { "_id" : "ids/1156324050", "_rev" : "1156324050", "_key" : "1156324050" } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "jensen" }}); { "_id" : "ids/1156520658", "_rev" : "1156520658", "_key" : "1156520658" } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "hansen" }}); [ArangoError 1210: cannot create document, unique constraint violated]