# Apply an interface to an asset model
<a name="interfaces-link-asset-model"></a>

When applying an interface to an asset model, you map asset model properties and hierarchies to their interface counterparts. For unmapped interface properties, corresponding properties are automatically created in the asset model. After linking, the service prevents changes to the asset model that would violate interface standards.

You can add one asset model to an interface at a time. However, multiple asset models can be linked to a single interface.

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#### [ Console ]

1. Navigate to the [Amazon IoT SiteWise console](https://console.amazonaws.cn/iotsitewise/) and choose **Models** from the navigation pane.

1. Select the asset model to which you want to apply an interface.

1. Choose **Link asset model** in the **Link asset models** section. This brings up the **Link interface** page.

1. In the **Asset models and interfaces** section, select an asset model from the **Select a model to link** dropdown menu.

1. In the **Property mappings** section, map each interface property to an existing asset model property or create a new property. Amazon IoT SiteWise automatically links properties with matching names in the asset model and interface.

1. Review the property mappings and choose **Link interface**.

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#### [ Amazon CLI ]

To apply an interface to an asset model, use the `PutAssetModelInterfaceRelationship` operation:

```
aws iotsitewise put-asset-model-interface-relationship \
  --asset-model-id "a1b2c3d4-5678-90ab-cdef-11111EXAMPLE" \ 
  --interface-asset-model-id "a1b2c3d4-5678-90ab-cdef-22222EXAMPLE" \
  --property-mapping-configuration '{
    "createMissingProperty": true,
    "matchByPropertyName": true,   
    "overrides": [
      {
        "assetModelPropertyId": "a1b2c3d4-5678-90ab-cdef-44444EXAMPLE",
        "interfaceAssetModelPropertyId": "a1b2c3d4-5678-90ab-cdef-33333EXAMPLE"      
      }
    ]
  }'
```

To retrieve information about an interface relationship, use the `DescribeAssetModelInterfaceRelationship` operation:

```
aws iotsitewise describe-asset-model-interface-relationship \
  --asset-model-id "a1b2c3d4-5678-90ab-cdef-11111EXAMPLE" \
  --interface-asset-model-id "a1b2c3d4-5678-90ab-cdef-22222EXAMPLE"
```

To list all asset models that have a specific interface applied to them, use the `ListInterfaceRelationships` operation:

```
aws iotsitewise list-interface-relationships \
  --interface-asset-model-id "a1b2c3d4-5678-90ab-cdef-22222EXAMPLE" \
  --max-results 10
```

To delete an interface relationship, use the `DeleteAssetModelInterfaceRelationship` operation:

```
aws iotsitewise delete-asset-model-interface-relationship \
  --asset-model-id "a1b2c3d4-5678-90ab-cdef-11111EXAMPLE" \
  --interface-asset-model-id "a1b2c3d4-5678-90ab-cdef-22222EXAMPLE"
```

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