How do you create and open a database in IndexedDB?

Question

Manish Sharma · Answer

To 
create and open a database in IndexedDB, you use the indexedDB.open() method. This is
asynchronous, and you interact with it via event handlers like
onsuccess, onerror, and onupgradeneeded.
Basic Steps to Create and Open an IndexedDB Database
Syntax
const request = indexedDB.open(databaseName, version);
databaseName: A string, like "MyAppDB"version: A number (e.g., 1) — used to trigger schema upgrades (like adding object stores)
Example: Create and Open a DB
const request = indexedDB.open("MyAppDB", 1);
request.onupgradeneeded = function(event) {
    const db = event.target.result;
    // Create an object store named "users" with "id" as the keyPath
    const store = db.createObjectStore("users", {
        keyPath: "id",
        autoIncrement: true
    });
    // Optional: create an index on "email"
    store.createIndex("emailIndex", "email", { unique: true });
    console.log("Object store and index created.");
};
request.onsuccess = function(event) {
    const db = event.target.result;
    console.log("Database opened successfully", db);
    // Now you can use `db.transaction(...)` to read/write
};
request.onerror = function(event) {
    console.error("Database error:", event.target.error);
};
Summary of Events
Event
Purpose
onupgradeneeded
Called when DB is created or upgraded (new version)
onsuccess
Called when DB is successfully opened
onerror
Called if opening DB fails
Tips
Use onupgradeneeded to:
Create object stores (db.createObjectStore(...))Define indexesMigrate data between versions
If the DB already exists with the same version, onupgradeneeded is
not triggered.You must perform all schema setup in onupgradeneeded.

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How do you create and open a database in IndexedDB?

Manish Sharma

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1 Answers

Basic Steps to Create and Open an IndexedDB Database

Syntax

Example: Create and Open a DB

Summary of Events

Tips

Liked By

Event	Purpose
`onupgradeneeded`	Called when DB is created or upgraded (new version)
`onsuccess`	Called when DB is successfully opened
`onerror`	Called if opening DB fails