arangosh> db.names.ensureIndex({ type: "persistent", fields: [ "first" ] }); { "id" : "names/15880", "type" : "persistent", "fields" : [ "first" ], "unique" : false, "sparse" : false, "isNewlyCreated" : true, "code" : 201 } arangosh> db.names.save({ "first" : "Tim" }); { "_id" : "names/15883", "_key" : "15883", "_rev" : "15883" } arangosh> db.names.save({ "first" : "Tom" }); { "_id" : "names/15887", "_key" : "15887", "_rev" : "15887" } arangosh> db.names.save({ "first" : "John" }); { "_id" : "names/15890", "_key" : "15890", "_rev" : "15890" } arangosh> db.names.save({ "first" : "Tim" }); { "_id" : "names/15893", "_key" : "15893", "_rev" : "15893" } arangosh> db.names.save({ "first" : "Tom" }); { "_id" : "names/15896", "_key" : "15896", "_rev" : "15896" }