Creating a Topic

:::caution Beta The semantic layer is in beta — the AI assistant does not query it automatically yet. You author and query topics directly. :::

Authoring a topic requires admin access.

1. Open Semantic Layer from the sidebar.
2. Click New topic, give it a name (the .yml extension is added for you), and pick the data source the topic is built on.
3. Define your cubes in YAML, then Save.

You never write data_source: in the YAML — your dropdown selection is applied to every cube automatically.

Example

cubes:
  - name: orders
    sql_table: public.orders

    dimensions:
      - name: id
        sql: id
        type: number
        primary_key: true
      - name: status
        sql: status
        type: string
      - name: created_at
        sql: created_at
        type: time

    measures:
      - name: count
        type: count
      - name: total_amount
        sql: amount
        type: sum

Supported data sources

A topic can only be built on a data source the semantic layer supports: PostgreSQL, MySQL, SQL Server, BigQuery, Athena, and Databricks. Other source types (APIs, files, NoSQL) cannot back a topic.

Joins are only possible between cubes built on the same data source — the semantic layer cannot join across two different sources in one query.