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.
Note:
This feature is available in Web Workers.Syntax
objectStore.deleteIndex(indexName);
Parameters
- indexName
- The name of the existing index to remove.
Return value
Exceptions
This method may raise a
DOMException
of one of the following types:
Exception | Description |
---|---|
InvalidStateError |
Occurs if the method was not called from
a versionchange transaction mode callback. |
TransactionInactiveError |
Occurs if the transaction this IDBObjectStore belongs to is not
active (e.g. has been deleted or removed.) In Firefox previous to version 41, an
InvalidStateError was raised in this case as well, which was
misleading; this has now been fixed (see bug 1176165.) |
NotFoundError |
Occurs if there is no index with the given name (case-sensitive) in the
database. |
Example
In the following example you can see
the IDBOpenDBRequest.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.)
var db;
// Let us open our database
var DBOpenRequest = window.indexedDB.open("toDoList", 4);
// these two event handlers act on the database being opened successfully, or not
DBOpenRequest.onerror = function(event) {
note.innerHTML += '<li>Error loading database.</li>';
};
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 = this.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 = function(event) {
var db = this.result;
db.onerror = function(event) {
note.innerHTML += '<li>Error loading database.</li>';
};
// Create an objectStore for this database
var 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 | Status | Comment |
---|---|---|
Indexed Database API 2.0 The definition of 'deleteIndex()' in that specification. |
Recommendation | |
Indexed Database API 2.0 The definition of 'deleteIndex()' in that specification. |
Recommendation |
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 example live.)