arangosh> db.ids.ensureIndex({ type: "persistent", fields: [ "name.first", "name.last" ], unique: true }); { "deduplicate" : true, "fields" : [ "name.first", "name.last" ], "id" : "ids/74797", "isNewlyCreated" : true, "name" : "idx_1646382081988624384", "selectivityEstimate" : 1, "sparse" : false, "type" : "persistent", "unique" : true, "code" : 201 } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "hansen" }}); { "_id" : "ids/74801", "_key" : "74801", "_rev" : "_ZXF6dXe--_" } arangosh> db.ids.save({ "name" : { "first" : "jens", "last": "jensen" }}); { "_id" : "ids/74803", "_key" : "74803", "_rev" : "_ZXF6dXe--B" } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "jensen" }}); { "_id" : "ids/74805", "_key" : "74805", "_rev" : "_ZXF6dXi---" } arangosh> db.ids.save({ "name" : { "first" : "hans", "last": "hansen" }}); [ArangoError 1210: unique constraint violated - in index idx_1646382081988624384 of type persistent over 'name.first, name.last'; conflicting key: 74801]