Semantic layer
Define glossary terms, reusable business meaning, metrics, and relationships.
Semantic layer
The semantic layer gives stable business meaning to source-specific structures.
Define shared terms
Use Glossary for organization language and semantic definitions for reusable metrics, dimensions, filters, and relationships. Define terms such as "active customer" or "net revenue" once, with an owner and clear edge cases.
Relationships
Confirm join keys, direction, and expected cardinality. Cross-source joins need an explicit, compatible key. A matching field name alone is not enough.
Metrics
Document aggregation, filters, units, grain, timezone, and exclusions. Test the definition against a known control value before wider use.
Change safely
Treat semantic changes like application changes:
- review impact on saved answers and dashboards
- test representative questions
- communicate changed meaning
- retain a visible owner
Plans show which definitions were applied, making semantic behavior inspectable rather than hidden in a prompt.