Entities

Definition: Entities are objects that have a distinct identity that runs through time and different states. They are defined by their identity rather than their attributes.

Characteristics:

• Unique Identity: Each entity has a unique identifier that distinguishes it from other entities.
• State and Behavior: Entities have attributes (state) and methods (behavior) that define their properties and actions.
• Lifespan: Entities typically have a longer lifespan and are often persisted in a database.

Example:

public class Order
{
    public int Id { get; set; }
    public string ProductName { get; set; }
    public int Quantity { get; set; }
    public decimal Price { get; set; }

    public decimal GetTotalPrice()
    {
        return Quantity * Price;
    }
}