The DataStoreCursor interface of the Data Store API represents a cursor that allows apps to iterate through a list of DataStoreTask objects representing the change history of the data store, for use when synchronizing the data.
The IDBEnvironment interface of the IndexedDB API contains the indexedDB property, which provides access to IndexedDB functionality. It is the top level IndexedDB interface implemented by the window and Worker objects.
The onchange event handler of the DataStore interface fires when a change is made to the data store. Its main use is to synchronize different apps that are using the data store when a change is made. When fired, this event returns a DataStoreChangeEvent, which can be used to handle the change that was just made. Alternatively, when the event fires you could create a DataStoreCursor and iterate through all the records, if needed.