The Beginner’s Guide to Understanding Object Relational Mapping (ORM)

Posted on March 3rd, 2023

In today’s fast-paced software development world, where time-to-market is critical, ORM plays a vital role in ensuring that developers can quickly build applications that can scale and adapt to changing requirements. Additionally, ORM provides numerous benefits such as improved productivity, increased maintainability and flexibility, and reduced complexity.

Therefore, it is essential for developers to understand ORM and its concepts to build efficient and scalable applications. This article aims to provide a comprehensive guide to understanding ORM. We will start by defining ORM and its importance in modern software development. Next, we will explain how ORM works and the advantages of using it. We will also explore popular ORM frameworks, best practices for using ORM, and the future of ORM in software development.

In summary, this article is a beginner’s guide to ORM, which provides insights into how ORM simplifies the way developers work with databases and the numerous benefits it provides. It will be an invaluable resource for developers who want to build scalable and efficient applications using ORM.

How is ORM different than traditional database management?

Traditional database access involves writing complex SQL queries to retrieve data from a database. This approach requires developers to have extensive knowledge of SQL, which can be time-consuming and error-prone. In contrast, ORM simplifies the process of working with databases by providing a higher level of abstraction.

ORM also enables developers to work with different databases, as it provides a database-agnostic interface. This means that developers can use the same code to interact with different databases without having to write custom code for each database.

In summary, Object Relational Mapping is a technique that provides an abstraction layer between the application and the database. It simplifies the way developers interact with databases by eliminating the need for writing complex SQL queries and enabling them to use familiar object-oriented concepts to access data. This approach provides a higher level of abstraction and enables developers to work with different databases using the same code.

How Does ORM Work?

Object Relational Mapping (ORM) creates a mapping between the object model of the application and the database schema. This mapping defines how objects in the application are translated to rows in the database tables and vice versa. For instance, consider a simple application that manages a list of users. The application has a User class with properties such as Name, Age, and Email. ORM creates a corresponding table in the database with columns such as Name, Age, and Email, and a row for each user.

When the application interacts with the database through ORM, the ORM framework automatically generates SQL queries to retrieve or update data. For example, suppose the application needs to retrieve a list of all users whose age is greater than 30. Instead of writing complex SQL queries, the developer can use ORM to retrieve the list of users using object-oriented syntax. The developer can write code such as User.objects.filter(age__gt=30), where User is the ORM model, objects is the ORM manager, and filter is the ORM query method. This approach provides a more intuitive and natural way to interact with the database, as developers can use familiar object-oriented concepts.

ORM also provides an object-relational identity management system, which ensures that objects in the application correspond to unique rows in the database. For example, if the application retrieves a user from the database and modifies its properties, ORM tracks these changes and generates the corresponding SQL statements to update the row in the database.

Common ORM Frameworks

There are several popular ORM frameworks available for various programming languages and platforms. Here are some of the most widely used ORM frameworks:

  1. Hibernate – Hibernate is a Java-based ORM framework that provides a robust and flexible solution for managing persistence. It supports a wide range of databases and provides a rich set of features, including caching, lazy loading, and optimistic locking.
  2. Entity Framework – Entity Framework is a popular ORM framework for .NET applications. It provides a simple and intuitive way to interact with databases and supports various database providers such as SQL Server, MySQL, and PostgreSQL.
  3. Django ORM – Django ORM is a high-level ORM framework for Python applications. It provides an easy-to-use interface for managing database relationships, transactions, and queries. It also supports various databases such as SQLite, PostgreSQL, and MySQL.
  4. Ruby on Rails ORM – Ruby on Rails ORM is a powerful ORM framework for Ruby applications. It provides a simple and concise way to interact with databases and supports various database providers such as MySQL, PostgreSQL, and SQLite.
  5. Sequelize – Sequelize is a popular ORM framework for Node.js applications. It provides a simple and intuitive way to manage persistence and supports various databases such as MySQL, PostgreSQL, and SQLite.
  6. Eloquent: Eloquent is an ORM (Object Relational Mapping) framework provided by the Laravel PHP framework. Eloquent allows developers to interact with databases using PHP code instead of writing SQL queries directly.

These ORM frameworks provide a wide range of features such as query optimization, caching, lazy loading, and transaction management. They also offer a rich set of tools and utilities for database migration, schema management, and data validation.

Choosing the right ORM framework for a particular application depends on various factors such as the programming language, platform, database requirements, and performance considerations. You should carefully evaluate the features and capabilities of different ORM frameworks before choosing one for their application.


In conclusion, ORM is a valuable tool for modern software development, and its popularity continues to grow. By providing a more intuitive and natural way to interact with databases, ORM frameworks enable developers to focus on business logic instead of dealing with low-level database interactions. The benefits of ORM include improved productivity, increased maintainability and flexibility, and improved code quality. With the help of ORM frameworks, developers can build better software more efficiently, reducing time-to-market and improving user satisfaction.

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