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docs/content/developer/iota-101/move-overview/structs-and-abilities/key.mdx
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| # The Key Ability | ||
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| We already covered two out of four abilities - | ||
| [Drop](./drop.mdx) and [Copy](./copy.mdx). They affect the behaviour of the value in a | ||
| scope and are not directly related to storage. It is time to cover the `key` ability, which allows | ||
| the struct to be stored. | ||
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| Historically, the `key` ability was created to mark the type as a _key in the storage_. A type with | ||
| the `key` ability could be stored at top-level in the storage, and could be _directly owned_ by an | ||
| account or address. With the introduction of the [Object Model](../../objects/object-model.mdx), the `key` ability | ||
| naturally became the defining ability for the object. | ||
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| ## Object Definition | ||
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| A struct with the `key` ability is considered an object and can be used in the storage functions. | ||
| The Sui Verifier will require the first field of the struct to be named `id` and have the type | ||
| `UID`. | ||
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| ```move | ||
| public struct Object has key { | ||
| id: UID, // required | ||
| name: String, | ||
| } | ||
| /// Creates a new Object with a Unique ID | ||
| public fun new(name: String, ctx: &mut TxContext): Object { | ||
| Object { | ||
| id: object::new(ctx), // creates a new UID | ||
| name, | ||
| } | ||
| } | ||
| ``` | ||
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| A struct with the `key` ability is still a struct, and can have any number of fields and associated | ||
| functions. There is no special handling or syntax for packing, accessing or unpacking the struct. | ||
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| However, because the first field of an object struct must be of type `UID` - a non-copyable and | ||
| non-droppable type (we will get to it very soon!), the struct transitively cannot have `drop` and | ||
| `copy` abilities. Thus, the object is non-discardable by design. | ||
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| ## Types with the `key` Ability | ||
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| Due to the `UID` requirement for types with `key`, none of the native types in Move can have the | ||
| `key` ability, nor can any of the [Standard Library](../../../../references/framework/move-stdlib/_category_.json) types. | ||
| The `key` ability is only present in the [IOTA Framework](../../../../references/framework/iota-framework/_category_.json) and | ||
| custom types. | ||
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| ## Next Steps | ||
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| Key ability defines the object in Move, and objects are intended to be _stored_. In the next section | ||
| we present the `iota::transfer` module, which provides native storage functions for objects. |
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docs/content/developer/iota-101/move-overview/structs-and-abilities/store.mdx
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| # Ability: Store | ||
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| ## Definition | ||
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| The `store` is a special ability that allows a type to be _stored_ in objects. This ability is | ||
| required for the type to be used as a field in a struct that has the `key` ability. Another way to | ||
| put it is that the `store` ability allows the value to be _wrapped_ in an object. | ||
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| :::info | ||
| The `store` ability also relaxes restrictions on transfer operations. We talk about it more in the | ||
| [Custome Transfer Rules](../../objects/transfers/custom-rules.mdx) section. | ||
| ::: | ||
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| ## Example | ||
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| In previous sections we already used types with the `key` ability: all objects must have a `UID` | ||
| field, which we used in examples; we also used the `Storable` type as a part of the `Config` struct. | ||
| The `Config` type also has the `store` ability. | ||
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| ```move | ||
| /// This type has the `store` ability. | ||
| public struct Storable has store {} | ||
| /// Config contains a `Storable` field which must have the `store` ability. | ||
| public struct Config has key, store { | ||
| id: UID, | ||
| stores: Storable, | ||
| } | ||
| /// MegaConfig contains a `Config` field which has the `store` ability. | ||
| public struct MegaConfig has key { | ||
| id: UID, | ||
| config: Config, // there it is! | ||
| } | ||
| ``` | ||
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| ## Types with the `store` Ability | ||
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| All native types (except for references) in Move have the `store` ability. This includes: | ||
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| - bool | ||
| - unsigned integers | ||
| - [vector](../../../../references/framework/move-stdlib/vector.mdx) | ||
| - [address](../../../../references/framework/move-stdlib/address.mdx) | ||
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| All of the types defined in the standard library have the `store` ability as well. This includes: | ||
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| - [Option](../../../../references/framework/move-stdlib/option.mdx) | ||
| - [String](../../../../references/framework/move-stdlib/string.mdx) | ||
| - [TypeName](../../../../references/framework/move-stdlib/type_name.mdx) |
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