A relationship associates an entity, such as an asset, a reference file, or a policy, with one or more related entities. The asset model diagram below helps to illustrate the function of content feed relationships.

The diagram shows how an asset is a combination of asset metadata, ownership data, reference material and embedded assets. In your content feed, however, these items appear as separate objects defined with separate tags: an <asset> tag contains asset metadata, an <ownership> tag contains ownership data, and a <file> tag identifies reference material. You use a relationship to tie these objects together.

There are two types of relationship:

• A "contains" relationship specifies that one asset in the relationship embeds the other item in the relationship. For example, a music video may contain a sound recording asset, and a sound recording contains a composition asset. A "contains" relationship is always a relationship between assets.

• An "associate" relationship creates a link between different types of objects. For example, this type of relationship allows you to unify asset metadata (<asset>), reference file(s) (<file>) and ownership data (<ownership>) into a single entity.

The default relationship type is the more flexible "associate". For that reason, many of the sample relationships in this document omit the type attribute.

Defining "contains" relationships

You can define a "contains" relationship from the perspective of the parent asset or the child asset. If a particular asset is embedded in multiple parents, such as a composition used in multiple sound recordings, you can use <relationship type="contained_by"> and specify the multiple parent assets as related items. The resulting parent-child relationship is the same regardless of which option you use in your feed.

To add child asset(s) to a parent asset:

1. Use the tag <relationship type="contains">.

2. Use exactly one <item> tag to identify the asset that embeds (contains) one or more other assets.

3. Use one <related_item> tag to identify each embedded (or contained) asset.

To embed a child asset into multiple parent assets:

1. Use the tag <relationship type="contained_by">.

2. Use exactly one <item> tag to identify the asset that is contained within one or more other assets.

3. Use one <related_item> tag to identify each asset that embeds the asset identified in the <item> tag.

Linking a trailer with a movie

<relationship type="contains">
  <item path="/feed/asset[@tag='trailer1'][@type='trailer']"/>
  <related_item path="/feed/asset[@tag='movie1'][@type='movie']"/>

<relationship>
  <item path="/feed/video[@tag='foo'][@type='trailer']"/>
  <related_item path="/external/video[@id='VIDEO_ID_1']"/>

Linking a television season with its episodes

<relationship type="contains">
  <item path="/feed/asset[title='Season Two']"/>
  <related_item path="/feed/asset[episode='23']"/>
  <related_item path="/feed/asset[episode='24']"/>
  <related_item path="/feed/asset[episode='25']"/>

Linking a composition and sound recordings

<relationship type="contains">
  <item path="/feed/asset[isrc='USZZ99900001']"/>
  <related_item path="/external/asset[iswc='T3452468001']"/>


<relationship type="contains">
  <item path="/feed/asset[isrc='USZZ32857251']"/>
  <related_item path="/external/asset[iswc='T3452468001']"/>

<relationship type="contained_by">
  <item path="/feed/asset[iswc='T3452468001']"/>
  <related_item path="/external/asset[isrc='USZZ99900001']"/>
  <related_item path="/external/asset[isrc='USZZ32857251']"/>

Defining "associate" relationships

An "associate" relationship links objects of different types. The effect of the relationship depends on the nature of the objects being related, as detailed in the table below.

To associate objects of different types:

1. Use the tag <relationship type="associate">, or just <relationship>. without a type argument.

2. Use one or more <item> tags to identify the object(s) that will then be associated with the related item(s).

3. Use one <related_item> tag to identify each associated object.

Note that if a relationship specifies multiple <item>s, YouTube will view those items as a single entity for the purpose of the relationship. The pseudo-example below shows a <relationship> tag that defines two relationships, "AB1" and "AB2":

<relationship type="associate">
  <item path="A"/>
  <item path="B"/>
  <related_item path="1"/>
  <related_item path="2"/>

The table below identifies the different kinds of "associate" relationships that your feed can define.

* Nguồn: Youtube