Active record vs Object mapper ORM
Tags: database, softwaredevelopment, java, php
Published: 2023-09-28 15:34:28

Object mapper and active record are two popular design patterns for object relational mapping (ORM). ORMs are used to map objects in code to relational databases. this allows developers to interact with the database in a more object oriented way, without having to write SQL queries.
The key difference between object mapper and active record is the level of abstraction.

**Object mapper:**
   - Object Mapper is an architectural pattern that maps objects to database tables.
   - It separates the business logic from the persistence layer, making the code more maintainable and testable.
   - It provides a layer of abstraction between the application and the database, allowing developers to work with objects instead of writing sql queries directly.
   - It can handle complex relationships between objects and perform database operations using methods like create, read, update, and delete (CRUD).
   - It is generally used in frameworks, such as Hibernate in Java or entity framework in dot net or Doctrine in php, provide features like lazy loading, and query optimization.
   - It generally offers better performance due to its optimized query generation.
   - It supports multiple databases by providing database agnostic querying and data mapping capabilities.
	
**Active record:**
   - Active record is an object relational mapping pattern used in frameworks like ruby on rails, laravel and etc.
   - It tightly couples the business logic with the database by representing each database table as a class and each row as an instance of that class.
   - It provides a simple and intuitive interface for performing database operations, as developers can directly manipulate objects to create, read, update, and delete records.
   - It automatically generates sql queries based on the object's state, reducing the need for manual sql query writing.
   - It simplifies the development process by handling the mapping between objects and database tables transparently.
   - It is suitable for smaller projects or applications where simplicity and rapid development are prioritized.
   - It may have performance limitations due to its automatic query generation.

When choosing between object mapper and active record, it is important to consider the specific needs of your application.
- if you need a highly flexible and scalable ORM, then object mapper is the better choice.
- if you need a simple and easy to use ORM, then active record is the better choice.

Here are some examples of when you might want to choose one pattern over the other:
**Object mapper:**
- You need a highly flexible and scalable ORM.
- You need to support complex database queries and relationships.
- You have a team of experienced developers who can implement and maintain an object mapper.

**Active record:**
- You need a simple and easy to use ORM.
- You are developing a small or medium sized application.
- You have a team of developers who are new to ORMs or who are more familiar with active record.

In summary, an object mapper separates the database logic from the business logic, providing a more flexible and abstract way to work with databases. on the other hand, active record tightly couples the business logic with the database, simplifying the development process but sacrificing some flexibility. The choice between them depends on the specific requirements and preferences of the project.