arangosh> db.ids.ensureIndex({ type: "persistent", fields: [ "name.first", "name.last" ], unique: true }); { "deduplicate" : true, "fields" : [ "name.first", "name.last" ], "id" : "ids/108630", "isNewlyCreated" : true, "sparse" : false, "type" : "persistent", "unique" : true, "code" : 201 } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "hansen" }}); { "_id" : "ids/108633", "_key" : "108633", "_rev" : "_XPb92fO--_" } arangosh> db.ids.save({ "name" : { "first" : "jens", "last": "jensen" }}); { "_id" : "ids/108637", "_key" : "108637", "_rev" : "_XPb92fO--B" } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "jensen" }}); { "_id" : "ids/108640", "_key" : "108640", "_rev" : "_XPb92fO--D" } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "hansen" }}); [ArangoError 1210: unique constraint violated - in index 108630 of type persistent over ["name.first","name.last"]; conflicting key: 108633]