arangosh> db.test.ensureIndex({ type: "skiplist", fields: [ "a[*]" ] }); { "id" : "test/16073", "type" : "skiplist", "fields" : [ "a[*]" ], "unique" : false, "sparse" : false, "isNewlyCreated" : true, "code" : 201 } arangosh> db.test.save({ a : [ 1, 2 ] }); { "_id" : "test/16076", "_key" : "16076", "_rev" : "16076" } arangosh> db.test.save({ a : [ 1, 3 ] }); { "_id" : "test/16080", "_key" : "16080", "_rev" : "16080" } arangosh> db.test.save({ a : null }); { "_id" : "test/16083", "_key" : "16083", "_rev" : "16083" }