Entity Framework (EF) is an object-relational mapping (ORM) framework developed by Microsoft. It enables developers to work with relational databases using domain-specific objects, eliminating the need to write low-level data access code manually. The architecture of Entity Framework can be divided into several key components:
At the core of Entity Framework is the data model, which represents the structure of the underlying database. It consists of entities (also known as domain objects or business objects) that map to database tables, and relationships between entities that represent the associations between tables.
The DbContext class is the main entry point for interacting with the database using Entity Framework. It represents a session with the database and provides a set of APIs for querying, inserting, updating, and deleting entities. The DbContext manages the connection to the database and tracks changes made to entities, allowing for efficient database operations.
Entity Data Model (EDM) is a conceptual model that describes the entities, relationships, and mapping details between the database and the application. It provides a higher-level abstraction over the database schema, allowing developers to work with entities and relationships instead of dealing directly with tables and columns. The EDM can be defined using attributes, fluent API, or XML-based mapping configurations.
Entity Framework supports LINQ (Language-Integrated Query), which allows developers to query the database using a strongly-typed, object-oriented syntax. LINQ to Entities translates LINQ queries into SQL queries and executes them against the underlying database. This provides a rich querying capability and improves type safety and compile-time checking.
Entity Framework is designed to work with different database providers, such as SQL Server, Oracle, MySQL, and PostgreSQL. Each provider implements the interfaces defined by Entity Framework, allowing the framework to generate the appropriate SQL statements and interact with the specific database engine.
Entity Framework tracks changes made to entities during their lifetime. It automatically detects modifications, additions, and deletions and generates the necessary SQL statements to synchronize the changes with the database when saving the changes. Change tracking allows for efficient and optimized updates to the database.
The mapping component in Entity Framework handles the mapping between the conceptual model (entities and relationships) and the storage model (database schema). It ensures that data is correctly persisted and retrieved from the database. Mapping can be defined using attributes, fluent API, or XML-based configurations.
Entity Framework supports different database providers through provider-specific implementations. These providers are responsible for translating Entity Framework operations into the specific SQL dialect and executing them against the database. Providers can also offer additional features specific to the database engine.
Entity Framework provides a high-level abstraction for working with databases, allowing developers to focus on the business logic of their applications rather than dealing with low-level data access code. It simplifies the development process and promotes code reusability by providing an object-oriented approach to database operations.