This is the new *Amazon CloudFormation Template Reference Guide*. Please update your bookmarks and links. For help getting started with CloudFormation, see the [Amazon CloudFormation User Guide](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/Welcome.html).

# AWS::IoTSiteWise::Asset AssetHierarchy
<a name="aws-properties-iotsitewise-asset-assethierarchy"></a>

Describes an asset hierarchy that contains a hierarchy's name and ID.

## Syntax
<a name="aws-properties-iotsitewise-asset-assethierarchy-syntax"></a>

To declare this entity in your Amazon CloudFormation template, use the following syntax:

### JSON
<a name="aws-properties-iotsitewise-asset-assethierarchy-syntax.json"></a>

```
{
  "[ChildAssetId](#cfn-iotsitewise-asset-assethierarchy-childassetid)" : String,
  "[ExternalId](#cfn-iotsitewise-asset-assethierarchy-externalid)" : String,
  "[Id](#cfn-iotsitewise-asset-assethierarchy-id)" : String,
  "[LogicalId](#cfn-iotsitewise-asset-assethierarchy-logicalid)" : String
}
```

### YAML
<a name="aws-properties-iotsitewise-asset-assethierarchy-syntax.yaml"></a>

```
  [ChildAssetId](#cfn-iotsitewise-asset-assethierarchy-childassetid): String
  [ExternalId](#cfn-iotsitewise-asset-assethierarchy-externalid): String
  [Id](#cfn-iotsitewise-asset-assethierarchy-id): String
  [LogicalId](#cfn-iotsitewise-asset-assethierarchy-logicalid): String
```

## Properties
<a name="aws-properties-iotsitewise-asset-assethierarchy-properties"></a>

`ChildAssetId`  <a name="cfn-iotsitewise-asset-assethierarchy-childassetid"></a>
The Id of the child asset.  
*Required*: Yes  
*Type*: String  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`ExternalId`  <a name="cfn-iotsitewise-asset-assethierarchy-externalid"></a>
The external ID of the hierarchy, if it has one. When you update an asset hierarchy, you may assign an external ID if it doesn't already have one. You can't change the external ID of an asset hierarchy that already has one. For more information, see [Using external IDs](https://docs.amazonaws.cn/iot-sitewise/latest/userguide/object-ids.html#external-ids) in the *Amazon IoT SiteWise User Guide*.  
*Required*: No  
*Type*: String  
*Pattern*: `[a-zA-Z0-9_][a-zA-Z_\-0-9.:]*[a-zA-Z0-9_]+`  
*Minimum*: `2`  
*Maximum*: `128`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`Id`  <a name="cfn-iotsitewise-asset-assethierarchy-id"></a>
The ID of the hierarchy. This ID is a `hierarchyId`.  
This is a return value and can't be set.
*Required*: No  
*Type*: String  
*Pattern*: `^[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}$`  
*Minimum*: `36`  
*Maximum*: `36`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)

`LogicalId`  <a name="cfn-iotsitewise-asset-assethierarchy-logicalid"></a>
The ID of the hierarchy. This ID is a `hierarchyId`.  
*Required*: No  
*Type*: String  
*Pattern*: `[^\u0000-\u001F\u007F]+`  
*Minimum*: `1`  
*Maximum*: `256`  
*Update requires*: [No interruption](https://docs.amazonaws.cn/AWSCloudFormation/latest/UserGuide/using-cfn-updating-stacks-update-behaviors.html#update-no-interrupt)