What is an entity in the context of programming or databases?

An entity is an abstract concept representing an object from the real world or an information structure that has a unique identity and possesses certain properties (attributes). In the context of databases or ORM frameworks, an entity often corresponds to a record in a database table or a PHP class that represents this record.

Examples:

• Person (name, age, address)
• Product (name, price, description)
• Order (number, date, list of products)

Main characteristics of an entity:

• Identity: Each entity is unique and can be identified (for example, by a primary key in a database).
• Properties (attributes): The entity has a set of characteristics that describe its state.
• Behavior: The entity may have methods that define its actions or interactions with other entities.

In PHP frameworks such as Doctrine or Eloquent, an entity is often represented as a PHP class:

<?php

// Represents the "Product" entity
class Product
{
    private int $id;
    private string $name;
    private float $price;

    public function getId(): int
    {
        return $this->id;
    }

    public function getName(): string
    {
        return $this->name;
    }

    public function setName(string $name): self
    {
        $this->name = $name;
        return $this;
    }

    public function getPrice(): float
    {
        return $this->price;
    }

    public function setPrice(float $price): self
    {
        $this->price = $price;
        return $this;
    }
}