Entity Framework Core vs NHibernate: What are the differences?

Introduction

Entity Framework Core and NHibernate are both object-relational mappers (ORMs) that provide a bridge between a relational database and an application's object-oriented model. While they serve the same purpose, there are key differences between the two.

1. Database Support: Entity Framework Core supports a wide range of databases, including SQL Server, PostgreSQL, MySQL, SQLite, and more. On the other hand, NHibernate has broader database support and can work with almost any database that has an ADO.NET provider.

2. Maturity: NHibernate has been around since 2004 and has a mature codebase with a stable feature set. Entity Framework Core, being a newer framework, has a more modern architecture and benefits from lessons learned from previous versions of Entity Framework. However, it may lack some of the advanced features and performance optimizations that NHibernate offers.

3. Mapping Approaches: Entity Framework Core uses a code-first or database-first approach for mapping database entities to objects. It provides a fluent API for configuring mappings and generating database schemas. NHibernate, on the other hand, supports multiple mapping approaches, including XML-based mapping files, attribute-based mapping, and convention-based mapping.

4. Querying: Entity Framework Core has a LINQ provider that allows developers to write strongly-typed queries using LINQ syntax. It also supports raw SQL queries and provides a query translation layer to convert LINQ queries into SQL statements. NHibernate also supports LINQ queries but has a more mature and feature-rich querying API, including support for HQL (Hibernate Query Language).

5. Performance: NHibernate is known for its performance optimizations, such as batch insert/update/delete operations, lazy loading, and caching. Entity Framework Core has made significant performance improvements over previous versions of Entity Framework but may still lag behind NHibernate in certain scenarios.

6. Community and Ecosystem: NHibernate has a vibrant and active community with extensive documentation, tutorials, and third-party extensions. Entity Framework Core, being a newer framework, is gaining popularity and has a growing ecosystem, but may not have the same level of community support and resources as NHibernate.

In summary, Entity Framework Core and NHibernate are both powerful ORM frameworks with their own strengths and weaknesses. While Entity Framework Core offers a more modern and streamlined development experience, NHibernate provides broader database support, advanced features, and performance optimizations. Ultimately, the choice between the two depends on the specific requirements and preferences of the project.