The get()
method of the IDBObjectStore
interface returns an IDBRequest
object, and, in a separate thread, returns the object store selected by the specified key. This is for retrieving specific records from an object store.
If a value is successfully found, then a structured clone of it is created and set as the result
of the request object.
openCursor()
method with the same key. That method provides a cursor if the record exists, and no cursor if it does not.SyntaxEdit
var request = objectStore.get(myItem);
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 IDBObjectStore 's transaction is inactive. |
DataError |
The key or key range provided contains an invalid key. |
InvalidStateError |
The IDBObjectStore has been deleted or removed. |
ExampleEdit
In the following code snippet, we open a read/write transaction on our database and get one specific record from object store using get()
— a sample record with the key "Walk dog". Once this data object is retrieved, you could then update it using normal JavaScript, then put it back into the database using a IDBObjectStore.put
operation. For a full working example, see our To-do Notifications app (view example live.)
// Let us open our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);
DBOpenRequest.onsuccess = function(event) {
note.innerHTML += '<li>Database initialised.</li>';
// store the result of opening the database in the db variable. This is used a lot below
db = DBOpenRequest.result;
// Run the getData() function to get the data from the database
getData();
};
function getData() {
// open a read/write db transaction, ready for retrieving the data
var transaction = db.transaction(["toDoList"], "readwrite");
// report on the success of opening the transaction
transaction.oncomplete = function(event) {
note.innerHTML += '<li>Transaction completed: database modification finished.</li>';
};
transaction.onerror = function(event) {
note.innerHTML += '<li>Transaction not opened due to error: ' + transaction.error + '</li>';
};
// create an object store on the transaction
var objectStore = transaction.objectStore("toDoList");
// clear all the data out of the object store
var objectStoreRequest = objectStore.get("Walk dog");
objectStoreRequest.onsuccess = function(event) {
// report the success of our get operation
note.innerHTML += '<li>Record retrieved.</li>';
var myRecord = objectStoreRequest.result;
};
};
ParametersEdit
- key
- The key or key range that identifies the record to be retrieved.
SpecificationsEdit
Specification | Status | Comment |
---|---|---|
Indexed Database API The definition of 'get()' in that specification. |
Editor's Draft |
Browser compatibilityEdit
See alsoEdit
- 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.)