Object Relational Mapping (ORM) is a technique used in creating a "bridge" between object-oriented programs and, in most cases, relational databases. An ORM tool is software designed to help OOP developers interact with relational databases. So instead of creating your own ORM software from scratch, you can make use of these tools. Object-relational mapping (ORM) is a key concept in the field of Database Management Systems (DBMS), addressing the bridge between the object-oriented programming approach and relational databases. ORM is critical in data interaction simplification, code optimization, and smooth blending of applications and databases. The purpose of this article is to explain ORM, covering its basic principles, benefits, and importance in modern software development.
- Object-Oriented Paradigm: ORM focuses on OOP principles that data and behavior are encapsulated within objects. In ORM, database entities are mapped to objects and developers use objects to interact and manipulate data in a fairly easy way.
- Mapping: The main purpose of ORM is object mapping to database tables and back. The mapping is defined through the metadata which represents interconnections between objects and the corresponding database schemas. Metadata of ORM frameworks is used for the generation of SQL queries and management of data flow between the application and the database.
- CRUD Operations: ORM makes CRUD operations easier. Developers can perform such operations on objects in their programming language; the ORM framework takes care of the translation of the operations to their corresponding SQL statements for the underlying database.
- Abstraction of Database Complexity: ORM insulates the developers from the complexity of SQL queries and database schema features. Illustration: Such abstraction enables the programmers to concentrate on their application’s logic and mechanics while avoiding lower-level database interactions.
- Portability: ORM ensures code portability through abstraction between the application and the database. Developers can switch between various database systems with little code changes since the object-relational mapping framework deals with the details of database-specific queries.
- Code Reusability: ORM boosts the code reusability by a classic way of relationship with databases. Developers can use a single codebase with different databases which makes it easier to maintain and scale applications.
- Maintenance and Scalability: ORM facilitates application maintenance via schema change and updates management. Aside from that, it enables scalability due to the ability for developers to optimize and fine-tune database interactions without major changes in application code.
There are many ORM tools available, but the following ORM tools are the most commonly used.
- Hibernate
- TopLink
- Eclipse Link
- Open JPA
- My Batis (formally known as iBatis)
