The onupgradeneeded property of the IDBOpenDBRequest interface is the event handler for the upgradeneeded event, triggered when a database of a bigger version number than the existing stored database is loaded.

The event passed to the handler is an IDBVersionChangeEvent.

Inside the event handler function you can include code to upgrade the database structure, as shown in the example below.

Note: This feature is available in Web Workers


IDBOpenDBRequest.onupgradeneeded = function(event) { ... };


In the following example you can see the onupgradeneeded handler being used to update the database structure if a database with a higher version number is loaded. For a full working example, see our To-do Notifications app (view example live.)

var db;

// Request version 3 of the database.
var request ="library", 3);

// This event handles the event whereby a new version of the
// database needs to be created. Either one has not been created
// before, or a new version number has been submitted via the
// line above.
request.onupgradeneeded = function(event) {
  db = request.result;

  db.onerror = function(errorEvent) {
    note.innerHTML += '<li>Error loading database.</li>';

  if (event.oldVersion < 1) {
    // Version 1 is the first version of the database.
    var store = db.createObjectStore("books", {keyPath: "isbn"});
    var titleIndex = store.createIndex("by_title", "title", {unique: true});
    var authorIndex = store.createIndex("by_author", "author");
  if (event.oldVersion < 2) {
    // Version 2 introduces a new index of books by year.
    var bookStore = request.transaction.objectStore("books");
    var yearIndex = bookStore.createIndex("by_year", "year");
  if (event.oldVersion < 3) {
    // Version 3 introduces a new object store for magazines with two indexes.
    var magazines = db.createObjectStore("magazines");
    var publisherIndex = magazines.createIndex("by_publisher", "publisher");
    var frequencyIndex = magazines.createIndex("by_frequency", "frequency");

request.onerror = function(event) {
  note.innerHTML += '<li>Error loading database.</li>';

request.onsuccess = function(event) {
  note.innerHTML += '<li>Database initialised.</li>';
  db = request.result;


Indexed Database API 3.0 (Indexed DB 3.0)
# dom-idbopendbrequest-onupgradeneeded

Browser compatibility

BCD tables only load in the browser

See also