In some cases, you might have a property in a repository item that references a large sub-tree of items. It can be inefficient to retrieve and cache the entire sub-tree of repository items every time the referring item is cached. In such a case, you can use the <attribute> tag to set the attribute cacheReferencesById=true. For example:
<property name="childProducts" ...>
...
<attribute name="cacheReferencesById" value="true"/>
</property>
The SQL Repository then will not store the repository items referred to, but will instead store only the repository IDs of the items referred to in the item cache.
