IDBIndex.get()
The get()
method of the IDBIndex
interface returns an IDBRequest
object, and, in a separate thread, finds either the value in the referenced object store that corresponds to the given key or the first corresponding value, if key
is set to an IDBKeyRange
.
If a value is successfully found, then a structured clone of it is created and set as the result
of the request object: this returns the record the key is associated with.
Syntax
var myIndex = objectStore.index('index'); var request = myIndex.get(key);
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. |
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 IDBIndex.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.
myIndex.get('Bungle')
is then used to retrieve the record with an lName
of Bungle
, and the result of that request is logged to the console when its success callback returns.
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'); var getRequest = myIndex.get('Bungle'); getRequest.onsuccess = function() { console.log(getRequest.result); } 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
- key Optional
- A key or
IDBKeyRange
that identifies the record to be retrieved. If this value is null or missing, the browser will use an unbound key range.
Specification
Specification | Status | Comment |
---|---|---|
Indexed Database API The definition of 'get()' 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/get