IDBOpenDBRequest
The IDBOpenDBRequest
interface of the IndexedDB API provides access to the results of requests to open or delete databases (performed using IDBFactory.open
and IDBFactory.deleteDatabase
), using specific event handler attributes.
Note: This feature is available in Web Workers
Instance properties
Also inherits properties from its parents IDBRequest
and EventTarget
.
Instance methods
No methods, but inherits methods from its parents IDBRequest
and EventTarget
.
Events
Events defined on parent interfaces, IDBRequest
and EventTarget
, can also be dispatched on IDBOpenDBRequest
objects.
Listen to these generic and specific events using addEventListener()
or by assigning an event listener to the oneventname
property of this interface.
Events specific to this interface are:
blocked
-
Fired when an open connection to a database is blocking a
versionchange
transaction on the same database. Also available via theonblocked
property. upgradeneeded
-
Fired when an attempt was made to open a database with a version number higher than its current version. Also available via the
onupgradeneeded
property.
Example
In the following example you can see the onupgradeneeded handler being used to update the database structure if a database with a higher version number is loaded. For a full working example, see our To-do Notifications app (view example live.)
js
let db;
// Let us open our database
const DBOpenRequest = window.indexedDB.open("toDoList", 4);
// these event handlers act on the database being opened.
DBOpenRequest.onerror = (event) => {
note.innerHTML += "<li>Error loading database.</li>";
};
DBOpenRequest.onsuccess = (event) => {
note.innerHTML += "<li>Database initialized.</li>";
// store the result of opening the database in the db
// variable. This is used a lot below
db = DBOpenRequest.result;
// Run the displayData() function to populate the task
// list with all the to-do list data already in the IDB
displayData();
};
// This event handles the event whereby a new version of
// the database needs to be created Either one has not
// been created before, or a new version number has been
// submitted via the window.indexedDB.open line above
// it is only implemented in recent browsers
DBOpenRequest.onupgradeneeded = (event) => {
const db = event.target.result;
db.onerror = (event) => {
note.innerHTML += "<li>Error loading database.</li>";
};
// Create an objectStore for this database
const objectStore = db.createObjectStore("toDoList", {
keyPath: "taskTitle",
});
// define what data items the objectStore will contain
objectStore.createIndex("hours", "hours", { unique: false });
objectStore.createIndex("minutes", "minutes", { unique: false });
objectStore.createIndex("day", "day", { unique: false });
objectStore.createIndex("month", "month", { unique: false });
objectStore.createIndex("year", "year", { unique: false });
objectStore.createIndex("notified", "notified", { unique: false });
};
Specifications
Specification |
---|
Indexed Database API 3.0 # idbopendbrequest |
Browser compatibility
BCD tables only load in the browser
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 the example live).