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Unleashing the Power of IndexedDB: Storing and Retrieving Data in Web Applications

IndexedDB is a powerful browser-based technology that helps web applications store and retrieve data. It can be used online and offline, making it an ideal choice for developers who want to create applications that work regardless of whether the user is connected to the internet or not.

IndexedDB is particularly useful for handling large amounts of data, making it a popular choice for performance-critical applications. In this article, we will explore what IndexedDB is and why web application developers should consider using it.

We will also discuss essential features such as databases, object stores, and indexes, with examples of how they are used in popular applications. What is IndexedDB?

IndexedDB is a browser-based, client-side technology that helps web applications store and retrieve large amounts of structured data. To put it another way, it is a database API that allows developers to build web applications that can persistently store data on a user’s computer.

The IndexedDB API provides a way to interact with web storage and query data using an object-oriented programming model. Why use IndexedDB?

Web applications that use IndexedDB can provide an offline experience, which means the application continues to work even when there is no internet connection. IndexedDB can store a substantial amount of data locally, making it ideal for large applications.

Compared to other storage solutions such as cookies or local storage, which limit the amount of data that can be stored, IndexedDB can store terabytes of data. IndexedDB is also designed to increase performance and improve the user experience.

As the data is stored locally, it can be accessed much faster, making the application much more responsive. IndexedDB also allows developers to write more complex queries and search through data much faster.

Applications that heavily use IndexedDB

Google Docs is an excellent example of a web application that heavily uses IndexedDB. It allows users to work on documents offline and syncs them when the user is online.

Online notepads, quizzes, todo lists, code sandboxes, and CMS are other examples that make heavy use of IndexedDB.

Structure of IndexedDB

IndexedDB is organized into three main components; databases, object stores, and indexes.


An IndexedDB database is a container for one or more object stores. A database is created using the `indexedDB.open()` method, which takes two parameters: a database name and a version number.

The version number is important as the IndexedDB API uses it to determine the schema of the database and upgrade it if needed.

Object stores

An object store within an IndexedDB database is similar to a table in a relational database. It stores records, which are JavaScript objects, and each record has a key that is unique within the object store.

Object stores can be created, retrieved, or deleted using the `createObjectStore()`, `getObjectStore()`, and `deleteObjectStore()` methods, respectively.


Indexes in IndexedDB are used to query data stored in an object store. They allow developers to retrieve data based on properties of objects within the store.

An index is created during the creation of an object store using the `createIndex()` method. An index is defined by a name, a key path, and an optional set of parameters.


IndexedDB is a powerful technology that allows developers to provide offline and large data storage capabilities to web applications natively. It provides a comprehensive solution to storing and retrieving structured data.

Additionally, it is designed to increase performance, making it an excellent choice for applications that handle a large amount of data. By using the structure discussed above, developers can create IndexedDB databases that can improve the user experience while providing a seamless online and offline experience.

Basic Concepts of IndexedDB

IndexedDB is a NoSQL database system that uses key-value pairs to store and retrieve data. Unlike traditional relational databases, such as MySQL or SQL Server, IndexedDB allows developers to store complex structured data using a simple key-value pair.

This approach is particularly useful when working with large amounts of data that can be efficiently organized into logical collections. IndexedDB is also transactional, which means that any update, insertion, or deletion of data is performed within a specific transaction.

This is important for maintaining data integrity, ensuring that all changes are completed successfully, or canceled if there is an error in the process. The IndexedDB API is asynchronous and works in coordination with the Document Object Model (DOM) events.

This means that developers must use event-based programming to interact with the API. Developers must listen to events such as `onsuccess` and `onerror` to know when a task is complete.

Another important concept of IndexedDB is that it follows the same-origin policy. This security policy restricts access to data that is stored on different origins or domains.

In other words, JavaScript code running on one website cannot directly read or modify data stored on another website. This provides a higher level of security and prevents malicious third-party scripts from accessing sensitive information.

Basic operations in IndexedDB

The first step in working with IndexedDB is the project structure and file organization. It’s essential to keep data access logic separate from other parts of the application, such as UI code.

This makes it easier to maintain and modify the codebase later. The next step is to check if IndexedDB is supported by the user’s browser.

Developers can check for support by calling the `window.indexedDB` property. If it’s undefined, IndexedDB is not supported, and the application will fall back to other storage systems.

To open a database, developers must use the `indexedDB.open(databaseName, databaseVersion)` method. This method returns an `IDBOpenDBRequest` object, which provides access to the database.

Once a database is open, the next step is to create object stores.

Object stores are similar to tables in relational databases; they contain collections of records.

Developers can create object stores during the `onupgradeneeded` event or when the database is created. Developers can also create indexes during this process, which can be used to query based on specific properties.

Inserting data into an object store is done inside a transaction. Transactions ensure data integrity; All operations performed within a transaction will either succeed entirely or fail entirely.

Developers must first obtain a transaction for the object store they want to modify using the `transaction()` method and then use the `put()` method to insert data. Reading data from an object store can be done in several ways.

To read data by key, developers can use the `get(key)` method. To query data using an index, developers can use the `index.get(key)` method.

To read all data from an object store, developers can use a cursor, which allows them to iterate through the data using the `objectStore.openCursor()` method. To delete a contact, developers must obtain a transaction, retrieve an object by key, and then use the `delete()` method.

Deleting is similar to inserting data into that it must happen within a transaction. Putting it all together, developers can create a complete project structure that includes all the necessary IndexedDB operations.

This approach should include the following:

1. Check if IndexedDB is supported


Open the database

3. Create object stores and indexes


Insert data into object stores

5. Read data from object stores


Delete data from object stores


IndexedDB provides web developers with a powerful tool for storing and retrieving data. Its key-value store is ideal for large amounts of data, and its structure allows for more complex structures than traditional SQL databases.

While there is a learning curve associated with working with IndexedDB, it is well worth the effort. This article covered the basic concepts of IndexedDB, including its transactional nature, asynchronous API, NoSQL design, and same-origin policy.

It also covered the basic operations, including project structure, checking for support, opening databases, creating object stores, inserting, reading, and deleting data. With these concepts and operations, developers can harness the power of IndexedDB to provide their users with a great experience, regardless of connectivity.

In summary, IndexedDB is a powerful browser-based technology used for storing and retrieving data. It is a NoSQL database system that stores data in key-value pairs and is transactional and follows the same-origin policy.

The IndexedDB API is asynchronous, and developers can perform basic operations such as creating object stores, inserting and reading data, and deleting data. By using IndexedDB, web developers can provide an offline experience, store large amounts of data, and improve performance and the user experience.

It has a learning curve, but the rewards are well worth the effort. In conclusion, IndexedDB is an essential technology for modern web applications, and developers should consider using it to create more powerful and responsive applications.

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