Web/API/IDBCursor/update

The update() method of the IDBCursor interface returns an IDBRequest object, and, in a separate thread, updates the value at the current position of the cursor in the object store. If the cursor points to a record that has just been deleted, a new record is created.

Be aware that you can't call update() (or IDBCursor.delete()) on cursors obtained from IDBIndex.openKeyCursor(). For such needs, you have to use IDBIndex.openCursor() instead.

Note: This feature is available in Web Workers.

Syntax

var anIDBRequest = myIDBCursor.update(value);

Parameters

value: The new value to be stored at the current position.

Return value

An IDBRequest object on which subsequent events related to this operation are fired.

Exceptions

This method may raise a DOMException of one of the following types:

Exception	Description
`TransactionInactiveError`	This IDBCursor's transaction is inactive.
`ReadOnlyError`	The transaction mode is read only.
`InvalidStateError`	The cursor was created using `IDBIndex.openKeyCursor`, is currently being iterated, or has iterated past its end.
`DataError`	The underlying object store uses in-line keys and the property in the value at the object store's key path does not match the key in this cursor's position.
`DataCloneError`	The data being stored could not be cloned by the internal structured cloning algorithm.

Example

In this simple fragment we create a transaction, retrieve an object store, then use a cursor to iterate through all the records in the object store. If the albumTitle of the current cursor is "A farewell to kings", we update year the album was released using var request = cursor.update();.

Note that you cannot change primary keys using cursor.update(), hence us not changing the album title; this would ruin the integrity of the data. In such a situation, you would have to delete the record altogether and then add a new one using IDBObjectStore.add. Note also that you can't directly put cursor.value into an update call, hence the below example using an intermediary updateData variable.

The cursor does not require us to select the data based on a key; we can just grab all of it. Also note that in each iteration of the loop, you can grab data from the current record under the cursor object using cursor.value.foo. For a complete working example, see our IDBCursor example ([[../../../../../../../mdn.github.io/IDBcursor-example/index|view example live]].)

function updateResult() {
  list.innerHTML = '';
  const transaction = db.transaction(['rushAlbumList'], 'readwrite');
  const objectStore = transaction.objectStore('rushAlbumList');

  objectStore.openCursor().onsuccess = function(event) {
    const cursor = event.target.result;
    if (cursor) {
      if (cursor.value.albumTitle === 'A farewell to kings') {
        const updateData = cursor.value;
          
        updateData.year = 2050;
        const request = cursor.update(updateData);
        request.onsuccess = function() {
          console.log('A better album year?');
        };
      };

      const listItem = document.createElement('li');
      listItem.innerHTML = '<strong>' + cursor.value.albumTitle + '</strong>, ' + cursor.value.year;
      list.appendChild(listItem);   
      cursor.continue();        
    } else {
      console.log('Entries displayed.');         
    }
  };
};

Specifications

Specification	Status	Comment
Indexed Database API 2.0The definition of 'update()' in that specification.	Recommendation
Indexed Database API DraftThe definition of 'update()' in that specification.	Recommendation

Browser compatibility

Update compatibility data on GitHub

	Desktop						Mobile
	Chrome	Edge	Firefox	Internet Explorer	Opera	Safari	Android webview	Chrome for Android	Firefox for Android	Opera for Android	Safari on iOS	Samsung Internet
`update`	Chrome Full support 24 Full support 24 No support 23 — 24 Prefixed' Prefixed' Implemented with the vendor prefix: webkit	Edge Full support 12	Firefox Full support 16 Full support 16 No support 10 — 16 Prefixed' Prefixed' Implemented with the vendor prefix: moz	IE Partial support 10	Opera Full support 15	Safari Full support 7	WebView Android Full support Yes	Chrome Android Full support Yes	Firefox Android Full support 22	Opera Android Full support 14	Safari iOS Full support 8	Samsung Internet Android Full support Yes

Legend

Full support: Full support
Partial support: Partial support
Requires a vendor prefix or different name for use.': Requires a vendor prefix or different name for use.