A single operation (create, update, remove) on a campaign asset.

[Proto definition ![GitHub](https://developers.google.com/site-assets/logo-github.svg)](https://github.com/googleapis/googleapis/blob/master/google/ads/googleads/v25/services/campaign_asset_service.proto)

| Fields ||
|---|---|
| ## `operation` Union field. The mutate operation. `operation` can be only one of the following: ||
| ### `create` | `https://developers.google.com/google-ads/api/reference/rpc/v25/CampaignAsset` Create operation: No resource name is expected for the new campaign asset. |
| ### `remove` | `string` Remove operation: A resource name for the removed campaign asset is expected, in this format: `customers/{customer_id}/campaignAssets/{campaign_id}~{asset_id}~{field_type}` |
| ### `update` | `https://developers.google.com/google-ads/api/reference/rpc/v25/CampaignAsset` Update operation: The campaign asset is expected to have a valid resource name. |
| ## `update_mask` | `https://protobuf.dev/reference/protobuf/google.protobuf#field-mask` FieldMask that determines which resource fields are modified in an update. |