Getting Started with Entity Framework in .NET

Getting Started with Entity Framework in .NET

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  Entity Framework (EF)in .NET Entity Framework (EF) is an Object-Relational Mapping (ORM) framework for .NET applications that facilitates interaction with relational databases. It simplifies the process of mapping objects in software to database tables and vice-versa, automatically generating necessary SQL to create or interact with database structures. Key Features and Usage: 1. Productivity Boost: EF reduces repetitive tasks of persisting data, allowing developers to focus more on application logic. 2. Automatic SQL Generation: EF can generate SQL commands for reading and writing data, reducing the need for manual SQL queries. 3. LINQ Support: Developers can use LINQ (Language Integrated Query) to query against domain objects, and EF executes these queries in the database. 4. Database Interaction: EF simplifies data interaction, materializing database results into domain objects. Architecture: 1. Data Providers: EF supports data providers that abstract the interaction between the application and database, translating SQL queries to native database commands. 2. Entity Client: This layer enables data access through entity objects, providing flexibility to work with entity SQL queries without needing explicit classes for the database schema. 3. Object Service: Provides an interface to interact with entities like memory objects, performing CRUD operations and tracking changes using Object Context. 4. Entity Data Model (EDM): The EDM consists of three core components: ● Storage Schema Model (SSDL): Represents the database schema. ● Conceptual Model (CSDL): Defines the entity model. ● Mapping Model: Maps the conceptual model to the storage model.
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  5. Metadata Services:A centralized API accessing metadata stored in the Entity, Mapping, and Storage layers. Key Concepts: 1. Entity Type: Describes the structure of a top-level concept in the model, like a "Student" with properties like "Student Name" and "Student ID." 2. Association Type: Describes relationships between entities, such as one-to-many or many-to-many relationships, and includes association ends and multiplicities. 3. Property: Defines the structure and characteristics of an entity, such as primitive data types (Int32, String, DateTime) or complex types. Core Entity Framework Class: ● DbContext: Represents the core of Entity Framework, handling entity object interactions, querying, and saving changes back to the database. It combines the Unit of Work and Repository patterns, tracking changes and managing entity operations. Query Types: 1. Adding New Entities: New entities are added using the Add method on DbSet. 2. Changing Existing Entities: Modify entity properties and save changes to persist updates. 3. Deleting Entities: Entities are removed using the Remove method, which cancels additions or deletes existing entities. Types of Entities: 1. POCO (Plain-Old CLR Objects): These are simple, framework-agnostic classes that map to the database entities. They support insert, query, delete, and update operations. 2. Dynamic Proxy: EF automatically generates proxy classes derived from POCO entities, enabling lazy loading and change tracking. This is useful for models created with Code First and EF Designer.
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  Relationships: Entity Framework supportsthree main types of relationships between tables: 1. One-to-Many Relationship: A single entity can be related to many others (e.g., one customer has many orders). 2. Many-to-Many Relationship: Multiple entities can be related to multiple others (e.g., students enrolled in many courses). 3. One-to-One Relationship: Each entity is related to exactly one other entity. In summary, Entity Framework simplifies database interaction by abstracting data operations into objects, supporting LINQ queries, and automatically handling SQL generation and database operations. It also provides flexibility in handling relationships, managing data models, and applying changes to the database efficiently. To go through this topic with practical examples, follow the StudySection Blogs.