Entity Component System

The Entity Component System (ECS) is the core of the Unity Data-Oriented Tech Stack. As the name indicates, ECS has three principal parts:

• Entities — the entities, or things, that populate your game or program.
• Components — the data associated with your entities, but organized by the data itself rather than by entity. (This difference in organization is one of the key differences between an object-oriented and a data-oriented design.)
• Systems — the logic that transforms the component data from its current state to its next state— for example, a system might update the positions of all moving entities by their velocity times the time interval since the previous frame.