indexeddb
Khóa học miễn phí IndexedDB – Deleting Data nhận dự án làm có lương
IndexedDB – Deleting Data
There are many situations where we need to delete data from the database; be it for storage purposes or just removing unwanted data to free up space. If we want to delete this unnecessary data from a database we can use the .delete() function
Syntax
const request = objectStore.delete(data);
We use the delete() function to delete the fields of the database which are not required.
Example
Let us look at an example script to delete data −
<!DOCTYPE html>
<html lang="en">
<head>
<title>Document</title>
</head>
<body>
<script>
const request = indexedDB.open("botdatabase",1);
request.onupgradeneeded = function(){
const db = request.result;
const store = db.createObjectStore("bots",{ keyPath: "id"});
}
request.onsuccess = function(){
document.write("database opened successfully");
const db = request.result;
const transaction=db.transaction("bots","readwrite");
const store = transaction.objectStore("bots");
store.add({id: 1, name: "jason",branch: "IT"});
store.add({id: 2, name: "praneeth",branch: "CSE"});
store.add({id: 3, name: "palli",branch: "EEE"});
store.add({id: 4, name: "abdul",branch: "IT"});
store.put({id: 4, name: "deevana",branch: "CSE
const deletename = store.delete(1);
deletename.onsuccess = function(){
document.write("id : 1 has been deleted");
}
transaction.oncomplete = function(){
db.close;
}
}
</script>
</body>
</html>
Output
database opened successfully id : 1 has been deleted
The database after deletion of id:1 =
0 2
{id: 2, name: ''praneeth'', branch: ''CSE''}
1 3
{id: 3, name: ''palli'', branch: ''EEE''}
2 4
{id: 4, name: ''deevana'', branch: ''CSE''}
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