# Add Components
An entity can have any number of components but only one in each storage.
Adding another component of the same type will replace the existing one.
## World
```rust, noplaypen
{{#include ../../../../tests/book/add_components.rs:world}}
```
## View
When adding components, the entities storage is only used to check if the [`EntityId`](https://docs.rs/shipyard/latest/shipyard/struct.EntityId.html) is alive.
We don't need exclusive access to the entities storage.
If you don't need to check if the entity is alive, you can use the [`AddComponent`](https://docs.rs/shipyard/latest/shipyard/trait.AddComponent.html) trait and do without the entities storage entirely.
```rust, noplaypen
{{#include ../../../../tests/book/add_components.rs:view}}
```