IDBTransaction: db property
The db
read-only property of the IDBTransaction
interface returns the database connection
with which this transaction is associated.
Note: This feature is available in Web Workers
Value
An IDBDatabase
object.
Examples
In the following code snippet, we open a read/write transaction on our database and add
some data to an object store. Note also the functions attached to transaction event
handlers to report on the outcome of the transaction opening in the event of success or
failure. At the end, we return the associated database connection using db
.
For a full working example, see our To-do Notifications app (view example live).
js
const note = document.getElementById("notifications");
// an instance of a db object for us to store the IDB data in
let db;
// Let us open our database
const DBOpenRequest = window.indexedDB.open("toDoList", 4);
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 addData() function to add the data to the database
addData();
};
function addData() {
// Create a new object ready for being inserted into the IDB
const newItem = [
{
taskTitle: "Walk dog",
hours: 19,
minutes: 30,
day: 24,
month: "December",
year: 2013,
notified: "no",
},
];
// open a read/write db transaction, ready for adding the data
const transaction = db.transaction(["toDoList"], "readwrite");
// report on the success of opening the transaction
transaction.oncomplete = (event) => {
note.innerHTML +=
"<li>Transaction completed: database modification finished.</li>";
};
transaction.onerror = (event) => {
note.innerHTML +=
"<li>Transaction not opened due to error. Duplicate items not allowed.</li>";
};
// create an object store on the transaction
const objectStore = transaction.objectStore("toDoList");
// add our newItem object to the object store
const objectStoreRequest = objectStore.add(newItem[0]);
objectStoreRequest.onsuccess = (event) => {
// report the success of the request (this does not mean the item
// has been stored successfully in the DB - for that you need transaction.onsuccess)
note.innerHTML += "<li>Request successful.</li>";
};
// Return the database (IDBDatabase) connection with which this transaction is associated
transaction.db;
}
Specifications
Specification |
---|
Indexed Database API 3.0 # ref-for-dom-idbtransaction-db① |
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).