# Object-Relational Mapping (ORM) Frameworks Object-Relational Mapping (ORM) is a programming technique that abstracts and converts data between incompatible type systems using OOP languages. ORM frameworks help to eliminate the type mismatch between the object and relational database models. ## How does ORM work? ORM frameworks provide methods to perform CRUD (Create, Read, Update, Delete) operations without writing SQL queries. They convert these method calls into SQL queries and execute them against the database. The returned result is also converted back to the object by the ORM framework. ```python # Example using Django ORM in Python from myapp.models import User # CREATE operation new_user = User(name='John Doe', email='john@doe.com') new_user.save() # READ operation user = User.objects.get(name='John Doe') # UPDATE operation user.email = 'john.doe@newmail.com' user.save() # DELETE operation user.delete() ``` ## Advantages and Disadvantages of ORM ORM frameworks simplify database operations and maintain the DRY (Don't Repeat Yourself) principle by minimizing the redundancy of code. They abstract the underlying SQL, thus reducing the need for in-depth SQL knowledge. On the flip side, ORM can lead to inefficient queries or over-complicated mappings in complex systems. It can also hide the nuances of SQL, leading to potential performance pitfalls. ## Popular ORM Frameworks - **Hibernate** (Java): Provides a framework for mapping an object-oriented domain model to a relational database. - **Django ORM** (Python): Offers a high-level, Pythonic abstraction to work with SQL. - **Sequelize** (Node.js): Promises-based ORM for Node.js, supports multiple SQL dialects. Understanding the concept and use of ORM frameworks can help in leveraging their benefits and mitigating their shortcomings. They can greatly simplify database operations, especially in web development where databases are a key component.