Object-Relational Mapping (ORM) is a programming technique for mapping data between a relational database and an object-oriented programming language. It’s a way to connect the two worlds of object-oriented programming and relational databases, which have different data structures and access methods.
ORM tools provide a layer of abstraction that lets developers work with objects in their code rather than directly interacting with the database. They handle the mapping between the database and the object-oriented code, so developers can use familiar object-oriented techniques to interact with the data.
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ORM tools typically come as application programming interfaces (APIs) for creating, reading, updating, and deleting objects in a database. They also provide a query language that lets developers retrieve data from a database using object-oriented syntax.
ORM tools can also perform caching, connection pooling, and transaction management. Some popular ORM frameworks include Hibernate for Java, Entity Framework for .NET, and Django ORM for Python.
What Are the Reasons for Using Object-Relational Mapping?
There are several reasons why developers choose to use ORM in their projects, including:
- Object-oriented programming: ORM lets developers work with familiar object-oriented programming concepts like inheritance and polymorphism when working with data stored in a relational database.
- Reduced boilerplate code: ORM frameworks typically provide a lot of boilerplate code for common database operations, such as create, read, update, and delete (CRUD) operations, which can save developers time and reduce the amount of code they have to write.
- Portability: ORM can provide a layer of abstraction that lets the same code work with multiple database systems. It can make switching between different database systems easier without rewriting a lot of code.
- Performance: ORM can help optimize database performance by providing features like caching and connection pooling.
- Security: ORM can help prevent Structured Query Language (SQL) injection attacks by automatically sanitizing user input and parameterizing SQL queries.
- Maintenance: ORM can help simplify maintaining an application by abstracting the database interactions and allowing for easier testing.
What Are the Differences between Object-Relational Mapping and SQL?
ORM and SQL are two different approaches to working with relational databases. While both are used to interact with the data stored in a relational database, they differ in several ways, namely:
- Abstraction level: ORM provides a higher level of abstraction compared to SQL. With ORM, developers work with objects and classes in their programming language, while SQL involves writing queries using a syntax specific to the database management system.
- Data model: ORM is designed to work with an object-oriented data model, while SQL is designed to work with a relational data model. While the object-oriented model allows for more complex data relationships and behaviors, the relational model is better suited for handling large amounts of data and ensuring data consistency.
- Complexity: ORM can be simpler to use than SQL, especially for developers who are more comfortable with object-oriented programming. However, ORM frameworks can also be complex and have a learning curve.
- Performance: SQL can often be faster than ORM for certain operations, especially for complex queries that involve multiple tables. However, ORM frameworks can provide features like caching and connection pooling to help optimize performance.
- Portability: SQL is generally more portable than ORM frameworks, as SQL queries can be used with any relational database management system. ORM frameworks are often specific to a particular programming language or database management system.
In sum, SQL is a more low-level approach to working with relational databases. Meanwhile, ORM provides a higher level of abstraction and is more suited for developers who prefer to work with object-oriented programming concepts.
What Are Examples of Object-Relational Mapping?
Many ORM frameworks are available for different programming languages and database management systems, including:
- Hibernate: Hibernate is a popular ORM framework for Java applications. It provides a high-level object-oriented interface to relational databases and supports a wide range of database management systems, including MySQL, Oracle, and Microsoft SQL Server.
- Entity Framework: Entity Framework is an ORM framework for .NET applications. It provides a set of APIs for interacting with data stored in relational databases and supports several database management systems, including Microsoft SQL Server, MySQL, and PostgreSQL.
- Django ORM: Django ORM is the built-in ORM framework written in Python for the Django web framework. It provides a high-level interface for interacting with relational databases and supports several database management systems, including MySQL, PostgreSQL, and SQLite.
Each framework has strengths and weaknesses, and choosing which one to use depends on a project’s needs.
ORM can help improve developer productivity, reduce the amount of boilerplate code required, increase the portability and performance of an application, and provide a more secure and maintainable way to interact with a database.
- ORM is a programming technique for mapping data between a relational database and an object-oriented programming language. It connects object-oriented programming and relational databases with different data structures and access methods.
- Programmers use ORM to enable object-oriented programming, reduce the need for boilerplate code, optimize database performance, ensure better security, and simplify maintenance. It is also portable.
- Compared to SQL, ORM provides a higher level of abstraction, works with an object-oriented model, is simpler to use, enables caching and connection pooling, and is specific to a particular programming language or database management system.