AttributeFieldMapping

Maps from feed attribute id to a placeholder or criterion field id.

Fields
`feed_attribute_id`	`int64` Immutable. Feed attribute from which to map.
`field_id`	`int64` Output only. The placeholder field ID. If a placeholder field enum is not published in the current API version, then this field will be populated and the field oneof will be empty. This field is read-only.
Union field `field` `field`. Placeholder or criterion field to be populated using data from the above feed attribute. Required. `field` can be only one of the following:
`sitelink_field`	`SitelinkPlaceholderField` Immutable. Sitelink Placeholder Fields.
`call_field`	`CallPlaceholderField` Immutable. Call Placeholder Fields.
`app_field`	`AppPlaceholderField` Immutable. App Placeholder Fields.
`location_field`	`LocationPlaceholderField` Output only. Location Placeholder Fields. This field is read-only.
`affiliate_location_field`	`AffiliateLocationPlaceholderField` Output only. Affiliate Location Placeholder Fields. This field is read-only.
`callout_field`	`CalloutPlaceholderField` Immutable. Callout Placeholder Fields.
`structured_snippet_field`	`StructuredSnippetPlaceholderField` Immutable. Structured Snippet Placeholder Fields.
`message_field`	`MessagePlaceholderField` Immutable. Message Placeholder Fields.
`price_field`	`PricePlaceholderField` Immutable. Price Placeholder Fields.
`promotion_field`	`PromotionPlaceholderField` Immutable. Promotion Placeholder Fields.
`ad_customizer_field`	`AdCustomizerPlaceholderField` Immutable. Ad Customizer Placeholder Fields
`dsa_page_feed_field`	`DsaPageFeedCriterionField` Immutable. Dynamic Search Ad Page Feed Fields.
`location_extension_targeting_field`	`LocationExtensionTargetingCriterionField` Immutable. Location Target Fields.
`education_field`	`EducationPlaceholderField` Immutable. Education Placeholder Fields
`flight_field`	`FlightPlaceholderField` Immutable. Flight Placeholder Fields
`custom_field`	`CustomPlaceholderField` Immutable. Custom Placeholder Fields
`hotel_field`	`HotelPlaceholderField` Immutable. Hotel Placeholder Fields
`real_estate_field`	`RealEstatePlaceholderField` Immutable. Real Estate Placeholder Fields
`travel_field`	`TravelPlaceholderField` Immutable. Travel Placeholder Fields
`local_field`	`LocalPlaceholderField` Immutable. Local Placeholder Fields
`job_field`	`JobPlaceholderField` Immutable. Job Placeholder Fields
`image_field`	`ImagePlaceholderField` Immutable. Image Placeholder Fields

AttributeFieldMapping

`feed_attribute_id`

`field_id`

`field`

`sitelink_field`

`call_field`

`app_field`

`location_field`

`affiliate_location_field`

`callout_field`

`structured_snippet_field`

`message_field`

`price_field`

`promotion_field`

`ad_customizer_field`

`dsa_page_feed_field`

`location_extension_targeting_field`

`education_field`

`flight_field`

`custom_field`

`hotel_field`

`real_estate_field`

`travel_field`

`local_field`

`job_field`

`image_field`