arangosh> db.ids.ensureIndex({ type: "persistent", fields: [ "name.first", "name.last" ], unique: true }); { "deduplicate" : true, "fields" : [ "name.first", "name.last" ], "id" : "ids/16132", "isNewlyCreated" : true, "sparse" : false, "type" : "persistent", "unique" : true, "code" : 201 } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "hansen" }}); { "_id" : "ids/16135", "_key" : "16135", "_rev" : "_WcJRge6--_" } arangosh> db.ids.save({ "name" : { "first" : "jens", "last": "jensen" }}); { "_id" : "ids/16139", "_key" : "16139", "_rev" : "_WcJRge6--B" } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "jensen" }}); { "_id" : "ids/16142", "_key" : "16142", "_rev" : "_WcJRgf---_" } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "hansen" }}); [ArangoError 1210: unique constraint violated - in index 16132 of type persistent over ["name.first","name.last"]; conflicting key: 16135]