Indexeddb 简明教程
IndexedDB - Using getAll() Function
在前几部分中，我们一次只从存储中检索对象。现在，我们可以检索所有数据或对象存储的子集。获取 all 方法使用 getAll() 函数返回对象存储中的所有对象
Syntax
ObjectStore.getAll(optionalConstraint);我们可以直接调用 getAll() 以返回存储在对象库中的所有对象，或者我们可以指定一个可选约束，例如从汽车数据库中获得红色轿车
Example
在以下示例脚本中，我们正在调用 getAll() 方法以一次性返回存储在对象库中的所有对象
<!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"});
store.createIndex("branch_db",["branch"],{unique: false});
}
request.onsuccess = function(){
document.write("database opened successfully");
const db = request.result;
const transaction=db.transaction("bots","readwrite");
const store = transaction.objectStore("bots");
const branchIndex = store.index("branch_db");
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 query = branchIndex.getAll(["IT"]);
query.onsuccess = function(){
document.write("query",query.result);
}
transaction.oncomplete = function(){
db.close;
}
}
</script>
</body>
</html>