IDBCursor.primaryKey
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.
Note: This feature is available in Web Workers
Value
A value of any data type.
Examples
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 |
---|
Indexed Database API 3.0 # ref-for-dom-idbcursor-primarykey① |
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.)