The primaryKey
read-only property of the IDBCursor
interface returns the cursor's current effective key. If the cursor is currently being iterated or has iterated outside its range, this is set to undefined. The cursor's primary key can be any data type.
Syntax
var value = cursor.primaryKey;
Value
A value of any data type.
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. Within each iteration we log the primary key of the cursor to the console, something like this (its the album title in each case, which is our primarykey):
Hemispheres
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 (view example live.)
function displayData() {
var transaction = db.transaction(['rushAlbumList'], "readonly");
var objectStore = transaction.objectStore('rushAlbumList');
objectStore.openCursor().onsuccess = function(event) {
var cursor = event.target.result;
if(cursor) {
var listItem = document.createElement('li');
listItem.innerHTML = cursor.value.albumTitle + ', ' + cursor.value.year;
list.appendChild(listItem);
console.log(cursor.primaryKey);
cursor.continue();
} else {
console.log('Entries all displayed.');
}
};
};
Specifications
Specification | Status | Comment |
---|---|---|
Indexed Database API The definition of 'primaryKey' in that specification. |
Recommendation | |
Indexed Database API 2.0 The definition of 'primaryKey' in that specification. |
Editor's Draft |
Browser compatibility
Feature | Chrome | Edge | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|---|
Basic support | 23webkit 24 |
(Yes) | 10 moz 16.0 (16.0) |
10, partial | 15 | 7.1 |
Available in workers | (Yes) | (Yes) | 37.0 (37.0) | ? | (Yes) | ? |
Indexed Database 2.0 | 58 | ? | ? | ? | 45 | ? |
Feature | Android Webview | Chrome for Android | Edge | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|---|---|
Basic support | (Yes) | (Yes) | (Yes) | 22.0 (22.0) | 1.0.1 | 10 | 22 | 8 |
Available in workers | (Yes) | (Yes) | (Yes) | 37.0 (37.0) | (Yes) | ? | (Yes) | ? |
Indexed Database 2.0 | 58 | 58 | ? | ? | ? | ? | 45 | ? |
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.)