The IDBCursor interface of the IndexedDB API represents a cursor
traversing or iterating over multiple records in a database.

The IDBCursorWithValue interface of the IndexedDB API represents
cursor for traversing or iterating over multiple records in a
It is the same as the `idb.IDBCursor`, except that it includes
value property.

The IDBDatabase interface of the IndexedDB API provides a connection
a database; you can use an IDBDatabase object to open a transaction
your database then create, manipulate, and delete objects (data)
that database. The interface provides the only way to get and
versions of the database.

IDBDatabase Events.

In the following code snippet, we make a request to open a database,
include handlers for the success and error cases. For a full
example, see our To-do Notifications app (view example live.)

IDBIndex interface of the IndexedDB API provides asynchronous
to an index in a database. An index is a kind of object store
looking up records in another object store, called the referenced
store. You use this interface to retrieve data.

A key range can be a single value or a range with upper and lower
or endpoints. If the key range has both upper and lower bounds,
it is bounded; if it has no bounds, it is unbounded. A bounded
range can either be open (the endpoints are excluded) or closed
endpoints are included). To retrieve all keys within a certain
you can use the following code constructs:

The IDBMutableFile interface provides access in read or write
to a file, dealing with all the necessary locks.

This example shows a variety of different uses of object stores,
updating the data structure with `idb.IDBObjectStore.createIndex`
an onupgradeneeded function, to adding a new item to our object
with `idb.IDBObjectStore.add`. For a full working example, see
To-do Notifications app (view example live.)

Also inherits methods from its parents `idb.IDBRequest` and `web.EventTarget`.

IDBOpenDBRequest Events.

The request object does not initially contain any information
the result of the operation, but once information becomes available,
event is fired on the request, and the information becomes available
the properties of the IDBRequest instance.

IDBRequest Events.

Note that as of Firefox 40, IndexedDB transactions have relaxed
guarantees to increase performance (see bug 1112702.) Previously
a readwrite transaction `idb.IDBTransaction.oncomplete` was fired
when all data was guaranteed to have been flushed to disk. In
40+ the complete event is fired after the OS has been told to
the data but potentially before that data has actually been flushed
disk. The complete event may thus be delivered quicker than before,
there exists a small chance that the entire transaction will
lost if the OS crashes or there is a loss of system power before
data is flushed to disk. Since such catastrophic events are rare
consumers should not need to concern themselves further.

IDBTransaction Events.

The IDBVersionChangeEvent interface of the IndexedDB API indicates
the version of the database has changed, as the result of an
event handler function.

The IDBVersionChangeRequest interface the IndexedDB API represents
request to change the version of a database. It is used only
the setVersion() method of IDBDatabase.