arangosh> db.names.ensureIndex({ type: "persistent", fields: [ "first" ] }); { "id" : "names/15120", "type" : "persistent", "fields" : [ "first" ], "unique" : false, "sparse" : false, "isNewlyCreated" : true, "code" : 201 } arangosh> db.names.save({ "first" : "Tim" }); { "_id" : "names/15123", "_key" : "15123", "_rev" : "_U-_q2ua---" } arangosh> db.names.save({ "first" : "Tom" }); { "_id" : "names/15127", "_key" : "15127", "_rev" : "_U-_q2ua--_" } arangosh> db.names.save({ "first" : "John" }); { "_id" : "names/15130", "_key" : "15130", "_rev" : "_U-_q2ue---" } arangosh> db.names.save({ "first" : "Tim" }); { "_id" : "names/15133", "_key" : "15133", "_rev" : "_U-_q2ue--_" } arangosh> db.names.save({ "first" : "Tom" }); { "_id" : "names/15136", "_key" : "15136", "_rev" : "_U-_q2ue--A" }