Build your first app with Rell on Chromia
This course is your starting point for building applications on Chromia using Rell, the programming language behind Chromia decentralized applications (dapps). You will create BookView, a simple book review app, while learning how to model data, write queries, and sign transactions.
What is Chromia?
Chromia is a relational blockchain that merges the features of a relational database with blockchain capabilities. With Chromia, dapps can be developed in a way that feels familiar to developers from various backgrounds, whether they are working on enterprise applications, games, or smaller projects.
A unique feature of Chromia is Rell, a specialized language designed for both blockchain and database use. Rell offers static typing, increased expressiveness, enhanced database security, and requires up to 10 times fewer lines of code compared to other blockchains.
To learn more about Chromia and its architecture, please explore the Chromia overview.
About the dapp
In this course, you will build a book review app where users can add books and book reviews, as well as provide ratings. The course will also cover various methods for refining and filtering reviews based on specific criteria.
What will I learn?
By the end of this course, you will have acquired the following skills:
- Define entities and establish their relationships.
- Retrieve data using queries while effectively applying filters.
- Understand basic validation techniques to secure your app.
- Learn how to sign and commit transactions using cryptographic signatures.
The outcome will be a fully functional dapp where users can add books, write reviews, and retrieve reviews based on personalized filters—all powered by Rell and the Chromia blockchain.
Related materials
This course relies on the following documentation to help you understand the underlying concepts and approaches:
| Section | Type | Documentation |
|---|---|---|
| Overview | Architecture | Nodes |
| Overview | Architecture | Dapps |
| Rell | Language features | Language features |
Repository link
The complete code repository for this course is available here: Book review course repository.