Defines a list of topic-level joins. Joins defined using this parameter will only be available to the topic where they are declared. This can be useful for one-off use cases, rare aliasing, or utilizing different join organization schemes. Refer to the Relationships & Joins documentation for more information about top-level and global relationships.User attributes ({{ omni_attributes.<user_attribute> }}) can be used in joins to create access filtered joins, which can be useful when you want to keep all rows in the dataset but limit access to the metadata.