mozilla
Your Search Results

    IDBObjectStore.clear()

    This article is in need of a technical review.

    The clear() method of the IDBObjectStore interface creates and immediately returns an IDBRequest object, and clears this object store in a separate thread. This is for deleting all the current data out of an object store.

    Clearing an object store consists of removing all records from the object store and removing all records in indexes that reference the object store.

    Syntax

    var request = objectStore.clear();

    Returns

    An IDBRequest object on which subsequent events related to this operation are fired.

    Exceptions

    This method may raise a DOMException with a DOMError of one of the following types:

    Exception Description
    ReadOnlyError The transaction associated with this operation is in read-only mode.
    TransactionInactiveError This IDBObjectStore's transaction is inactive.
     

    Example

    In the following code snippet, we open a read/write transaction on our database and clear all the current data out of the object store using clear(). 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 clearData() function to clear all the data form the object store
      clearData();
    };
    
    function clearData() {
      // open a read/write db transaction, ready for clearing 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.clear();
    
      objectStoreRequest.onsuccess = function(event) {
        // report the success of our clear operation
        note.innerHTML += '<li>Data cleared.</li>';
      };
    };

    Specification

    Specification Status Comment
    Indexed Database API
    The definition of 'clear()' in that specification.
    Candidate Recommendation  

    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
    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 Not supported

    See also

    Document Tags and Contributors

    Contributors to this page: fscholz, chrisdavidmills
    Last updated by: fscholz,