IDBIndex.openCursor()
The openCursor()
method of the IDBIndex
interface returns an IDBRequest
object, and, in a separate thread, creates a cursor over the specified key range.
The method sets the position of the cursor to the appropriate record, based on the specified direction.
- If the key range is not specified or is null, then the range includes all the records.
- A success event is always fired on the result object.
Syntax
var myIndex = objectStore.index('index'); var request = myIndex.openCursor(range,direction);
Returns
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 IDBIndex 's transaction is inactive. |
TypeError |
The value for the direction parameter is invalid. |
DataError |
The key or key range provided contains an invalid key. |
InvalidStateError |
The IDBIndex has been deleted or removed. |
Example
In the following example we open a transaction and an object store, then get the index lName
from a simple contacts database. We then open a basic cursor on the index using openCursor()
— this works the same as opening a cursor directly on an ObjectStore
using IDBObjectStore.openCursor
except that the returned records are sorted based on the index, not the primary key.
Finally, we iterate through each record, and insert the data into an HTML table. For a complete working example, see our IDBIndex-example demo repo (View the example live.)
function displayDataByIndex() { tableEntry.innerHTML = ''; var transaction = db.transaction(['contactsList'], 'readonly'); var objectStore = transaction.objectStore('contactsList'); var myIndex = objectStore.index('lName'); myIndex.openCursor().onsuccess = function(event) { var cursor = event.target.result; if(cursor) { var tableRow = document.createElement('tr'); tableRow.innerHTML = '<td>' + cursor.value.id + '</td>' + '<td>' + cursor.value.lName + '</td>' + '<td>' + cursor.value.fName + '</td>' + '<td>' + cursor.value.jTitle + '</td>' + '<td>' + cursor.value.company + '</td>' + '<td>' + cursor.value.eMail + '</td>' + '<td>' + cursor.value.phone + '</td>' + '<td>' + cursor.value.age + '</td>'; tableEntry.appendChild(tableRow); cursor.continue(); } else { console.log('Entries all displayed.'); } }; };
Parameters
- range Optional
- A key or
IDBKeyRange
to use as the cursor's range. If nothing is passed, this will default to a key range that selects all the records in this object store. - direction Optional
- The cursor's direction. See IDBCursor Constants for possible values.
Specification
Specification | Status | Comment |
---|---|---|
Indexed Database API The definition of 'openCursor()' in that specification. |
Editor's Draft |
Browser compatibility
Feature | Chrome | Firefox (Gecko) | Internet Explorer | Opera | Safari (WebKit) |
---|---|---|---|---|---|
Basic support | 23webkit 24 |
10 moz 16.0 (16.0) |
10, partial | 15 | 7.1 |
Available in workers | (Yes) | 37.0 (37.0) | ? | (Yes) | ? |
Feature | Android | Firefox Mobile (Gecko) | Firefox OS | IE Phone | Opera Mobile | Safari Mobile |
---|---|---|---|---|---|---|
Basic support | 4.4 | 22.0 (22.0) | 1.0.1 | 10 | 22 | 8 |
Available in workers | (Yes) | 37.0 (37.0) | (Yes) | ? | (Yes) | ? |
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.)
License
© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/idbindex/opencursor