IDBObjectStore.put() - Web APIs 编辑

The put() method of the IDBObjectStore interface updates a given record in a database, or inserts a new record if the given item does not already exist.

It returns an IDBRequest object, and, in a separate thread, creates a structured clone of the value and stores the cloned value in the object store. This is for adding new records, or updating existing records in an object store when the transaction's mode is readwrite. If the record is successfully stored, then a success event is fired on the returned request object with the result set to the key for the stored record, and the transaction set to the transaction in which this object store is opened.

The put method is an update or insert method. See the IDBObjectStore.add method for an insert only method.

Bear in mind that if you have a IDBCursor to the record you want to update, updating it with IDBCursor.update() is preferable to using IDBObjectStore.put(). Doing so makes it clear that an existing record will be updated, instead of a new record being inserted.

Note:

Syntax

let request = objectStore.put(item);
let request = objectStore.put(item, key);

Parameters

item

The item you wish to update (or insert).

key Optional

The primary key of the record you want to update (e.g. from IDBCursor.primaryKey). This is only needed for object stores that have an autoIncrement primary key, therefore the key is not in a field on the record object. In such cases, calling put(item) will always insert a new record, because it doesn't know what existing record you might want to modify.

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:

Parameters

value

The value to be stored.

key

The key to use to identify the record. If unspecified, it results to null. If the object store has a key generator (e.g. autoincrement) the key of the object must be passed in to update the object.

Example

The following example requests a given record title; when that request is successful the onsuccess function gets the associated record from the IDBObjectStore (made available as objectStoreTitleRequest.result), updates one property of the record, and then puts the updated record back into the object store in another request with put(). For a full working example, see our To-do Notifications app (view example live.)

const title = "Walk dog";

// Open up a transaction as usual
const objectStore = db.transaction(['toDoList'], "readwrite").objectStore('toDoList');

// Get the to-do list object that has this title as it's title
const objectStoreTitleRequest = objectStore.get(title);

objectStoreTitleRequest.onsuccess = () => {
  // Grab the data object returned as the result
  const data = objectStoreTitleRequest.result;

  // Update the notified value in the object to "yes"
  data.notified = "yes";

  // Create another request that inserts the item back into the database
  const updateTitleRequest = objectStore.put(data);

  // Log the transaction that originated this request
  console.log("The transaction that originated this request is " + updateTitleRequest.transaction);

  // When this new request succeeds, run the displayData() function again to update the display
  updateTitleRequest.onsuccess = () => {
    displayData();
  };
};

Specification

Browser compatibility

BCD tables only load in the browser

See also

• Using IndexedDB
• Starting transactions: IDBDatabase
• Using transactions: IDBTransaction
• Setting a range of keys: IDBKeyRange
• Retrieving and making changes to your data: IDBObjectStore
• Using cursors: IDBCursor
• Reference example: To-do Notifications (view example live.)