Object-Relational Mapping (ORM) in Node.js is a process that facilitates mapping between objects and relational database systems, providing a structured approach for CRUD operations by abstracting SQL queries into object manipulation. This abstraction layer enhances readability and development speed but can introduce inefficiencies, especially in complex queries, and does not cover all database operations, necessitating raw SQL knowledge. While tools like Sequelize, Knex, and Objection.js offer varying levels of abstraction, they each have trade-offs in terms of performance, complexity, and ease of use. The choice between low-level database drivers, mid-level query builders, and high-level ORMs should be based on specific project needs, balancing control, performance, and developer productivity. Despite its limitations, ORM is popular for its ease of use, ability to work with multiple databases, and features like transaction support and SQL injection protection.