indexeddb

Khóa học miễn phí IndexedDB – Deleting Data nhận dự án làm có lương

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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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