A semantic join is the multimodal equivalent of a SQL JOIN. In structured databases, JOINs combine rows from different tables using foreign keys. In a multimodal data warehouse, enrich stages combine results from different collections using embedding similarity or document relationships. This enables cross-referencing without pre-defined foreign keys.
After a retrieval pipeline produces results from one collection (e.g., media library search), an enrich stage queries a second collection (e.g., brand safety scores) to attach contextual data to each result. The join can be by document ID, semantic similarity, or metadata matching.