update not work

[值得拥有]

class func primaryKeys() -> Set<String> {
    return ["id"]
}

static func save(array: [DisModel]) {
    let database = SwiftyDB(databaseName: "dogtopia")
//        database.deleteObjectsForType(DisModel.self)
    database.addObjects(array, update: true)
 }

As above, even if I put the update parameter is true, add object database is to be repeated.

[值得拥有]

it's my wrong.