IDBObjectStore
==============

The **`IDBObjectStore`** interface of the IndexedDB API represents an object store in a database. Records within an object store are sorted according to their keys. This sorting enables fast insertion, look-up, and ordered retrieval.

**Note:** This feature is available in Web Workers

Instance properties
-------------------

`IDBObjectStore.indexNames` Read only 

A list of the names of indexes on objects in this object store.

`IDBObjectStore.keyPath` Read only 

The key path of this object store. If this attribute is `null`, the application must provide a key for each modification operation.

`IDBObjectStore.name`

The name of this object store.

`IDBObjectStore.transaction` Read only 

The `IDBTransaction` object to which this object store belongs.

`IDBObjectStore.autoIncrement` Read only 

The value of the auto increment flag for this object store.

Instance methods
----------------

`IDBObjectStore.add()`

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 to an object store.

`IDBObjectStore.clear()`

Creates and immediately returns an `IDBRequest` object, and clears this object store in a separate thread. This is for deleting all current records out of an object store.

`IDBObjectStore.count()`

Returns an `IDBRequest` object, and, in a separate thread, returns the total number of records that match the provided key or `IDBKeyRange`. If no arguments are provided, it returns the total number of records in the store.

`IDBObjectStore.createIndex()`

Creates a new index during a version upgrade, returning a new `IDBIndex` object in the connected database.

`IDBObjectStore.delete()`

returns an `IDBRequest` object, and, in a separate thread, deletes the store object selected by the specified key. This is for deleting individual records out of an object store.

`IDBObjectStore.deleteIndex()`

Destroys the specified index in the connected database, used during a version upgrade.

`IDBObjectStore.get()`

Returns an `IDBRequest` object, and, in a separate thread, returns the store object store selected by the specified key. This is for retrieving specific records from an object store.

`IDBObjectStore.getKey()`

Returns an `IDBRequest` object, and, in a separate thread retrieves and returns the record key for the object in the object stored matching the specified parameter.

`IDBObjectStore.getAll()`

Returns an `IDBRequest` object retrieves all objects in the object store matching the specified parameter or all objects in the store if no parameters are given.

`IDBObjectStore.getAllKeys()`

Returns an `IDBRequest` object retrieves record keys for all objects in the object store matching the specified parameter or all objects in the store if no parameters are given.

`IDBObjectStore.index()`

Opens an index from this object store after which it can, for example, be used to return a sequence of records sorted by that index using a cursor.

`IDBObjectStore.openCursor()`

Returns an `IDBRequest` object, and, in a separate thread, returns a new `IDBCursorWithValue` object. Used for iterating through an object store by primary key with a cursor.

`IDBObjectStore.openKeyCursor()`

Returns an `IDBRequest` object, and, in a separate thread, returns a new `IDBCursor`. Used for iterating through an object store with a key.

`IDBObjectStore.put()`

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 updating existing records in an object store when the transaction's mode is `readwrite`.

Example
-------

This example shows a variety of different uses of object stores, from updating the data structure with `IDBObjectStore.createIndex` inside an `onupgradeneeded` function, to adding a new item to our object store with `IDBObjectStore.add`. For a full working example, see our To-do Notifications app (view example live).


```js
// Let us open our database
const DBOpenRequest = window.indexedDB.open("toDoList", 4);

DBOpenRequest.onsuccess = (event) => {
  note.innerHTML += "<li>Database initialized.</li>";

  // store the result of opening the database in db.
  db = DBOpenRequest.result;
};

// 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 window.indexedDB.open line above
DBOpenRequest.onupgradeneeded = (event) => {
  const db = event.target.result;

  db.onerror = (event) => {
    note.innerHTML += "<li>Error loading database.</li>";
  };

  // Create an objectStore for this database

  const objectStore = db.createObjectStore("toDoList", {
    keyPath: "taskTitle",
  });

  // define what data items the objectStore will contain

  objectStore.createIndex("hours", "hours", { unique: false });
  objectStore.createIndex("minutes", "minutes", { unique: false });
  objectStore.createIndex("day", "day", { unique: false });
  objectStore.createIndex("month", "month", { unique: false });
  objectStore.createIndex("year", "year", { unique: false });

  objectStore.createIndex("notified", "notified", { unique: false });

  note.innerHTML += "<li>Object store created.</li>";
};

// Create a new item to add in to the object store
const newItem = [
  {
    taskTitle: "Walk dog",
    hours: 19,
    minutes: 30,
    day: 24,
    month: "December",
    year: 2013,
    notified: "no",
  },
];

// open a read/write db transaction, ready for adding the data
const transaction = db.transaction(["toDoList"], "readwrite");

// report on the success of the transaction completing, when everything is done
transaction.oncomplete = (event) => {
  note.innerHTML += "<li>Transaction completed.</li>";
};

transaction.onerror = (event) => {
  note.innerHTML +=
    "<li>Transaction not opened due to error. Duplicate items not allowed.</li>";
};

// create an object store on the transaction
const objectStore = transaction.objectStore("toDoList");
// make a request to add our newItem object to the object store
const objectStoreRequest = objectStore.add(newItem[0]);

objectStoreRequest.onsuccess = (event) => {
  note.innerHTML += "<li>Request successful .</li>";
};
```

Specifications
--------------

| Specification |
| --- |
| Indexed Database API 3.0 # object-store-interface |

Browser compatibility
---------------------

BCD tables only load in the browser with JavaScript enabled. Enable JavaScript to view data.

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 the example live).