Indexeddb 简明教程

IndexedDB - Reading Data

我们将数据输入数据库，并且我们需要调用数据以查看更改以及用于其他各种目的。

We enter data into the database, and we need to call the data to view the changes and also for various other purposes.

我们必须对对象存储调用 get() 方法才能读取此数据。get 方法接收要从存储中检索的对象的主键。

We must call the get() method on the object store to read this data. The get method takes the primary key of the object you want to retrieve from the store.

Syntax

var request = objectstore.get(data);

在这里，我们请求 objectstore 使用 get() 函数获取数据。

Here, we are requesting the objectstore to get the data using get() function.

Example

以下示例是如何实现请求 objectstore 以获取数据的 −

Following example is an implementation of requesting the objectstore to get the 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"});
         const idquery = store.get(4);
         idquery.onsuccess = function(){
            document.write("idquery",idquery.result);
         }
         transaction.oncomplete = function(){
            db.close;
         }
      }
   </script>
</body>
</html>

Output

database opened successfully
idquery {id: 4, name: 'abdul', branch: 'IT'}