IDBObjectStore: deleteIndex() method
Note: This feature is available in Web Workers.
The deleteIndex()
method of the
IDBObjectStore
interface destroys the index with the specified name in
the connected database, used during a version upgrade.
Note that this method must be called only from a VersionChange
transaction
mode callback. Note that this method synchronously modifies the
IDBObjectStore.indexNames
property.
Syntax
deleteIndex(indexName)
Parameters
indexName
-
The name of the existing index to remove.
Return value
None (undefined
).
Exceptions
InvalidStateError
DOMException
-
Thrown if the method was not called from a
versionchange
transaction mode callback. TransactionInactiveError
DOMException
-
Thrown if the transaction this
IDBObjectStore
belongs to is not active (e.g. has been deleted or removed.) NotFoundError
DOMException
-
Thrown if there is no index with the given name (case-sensitive) in the database.
Examples
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.
IDBObjectStore.createIndex
is used to create new indexes on the object
store, after which we delete the unneeded old indexes with deleteIndex()
.
For a full working example, see our
To-do Notifications app (view example live).
let db;
// Let us open our database
const DBOpenRequest = window.indexedDB.open("toDoList", 4);
// these two event handlers act on the database being opened successfully, or not
DBOpenRequest.onerror = (event) => {
note.appendChild(document.createElement("li")).textContent =
"Error loading database.";
};
DBOpenRequest.onsuccess = (event) => {
note.appendChild(document.createElement("li")).textContent =
"Database initialized.";
// store the result of opening the database in the db variable. This is used a lot below
db = event.target.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.appendChild(document.createElement("li")).textContent =
"Error loading database.";
};
// 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 });
objectStore.deleteIndex("seconds");
objectStore.deleteIndex("contact");
};
Specifications
Specification |
---|
Indexed Database API 3.0 # ref-for-dom-idbobjectstore-deleteindex① |
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).