What is an entity in the Entity Framework with Examples?
Sardar Mudassar Ali Khan
Posted on May 31, 2023
In the context of Entity Framework, an entity refers to a class that represents a table in a relational database. It is a fundamental concept in the Object-Relational Mapping (ORM) provided by Entity Framework, which allows developers to interact with the database using objects and their relationships, rather than writing raw SQL queries.
An entity typically corresponds to a row in a database table, and each property of the entity represents a column in that table. The relationships between entities are modeled through navigation properties, which define associations between tables.
Here's an example to illustrate the concept of entities in Entity Framework:
Let's say we have a database with two tables: "Customers" and "Orders". We can define two entity classes in our application to represent these tables:
public class Customer
{
public int CustomerId { get; set; }
public string Name { get; set; }
public ICollection<Order> Orders { get; set; }
}
public class Order
{
public int OrderId { get; set; }
public DateTime OrderDate { get; set; }
public Customer Customer { get; set; }
}
In this example, the Customer
class represents the "Customers" table, and the Order
class represents the "Orders" table. Each property in these classes corresponds to a column in the respective table. The CustomerId
property in the Customer
class, for example, maps to the "CustomerId" column in the "Customers" table.
The ICollection<Order> Orders
property in the Customer
class represents a one-to-many relationship between customers and orders. It allows us to navigate from a customer to their associated orders.
By using Entity Framework, we can perform operations such as querying, inserting, updating, and deleting data in the database using these entity classes, without having to write explicit SQL statements. Entity Framework handles the mapping between the entities and the database tables, allowing us to work with objects in a more intuitive manner.
Note that this is a simplified example to illustrate the concept of entities in Entity Framework. In a real-world application, you would typically have more complex entity models with additional properties and relationships.
Posted on May 31, 2023
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