Documenting Dbt Models

Documenting dbt Models

When to use

• Adding or improving descriptions for models, columns, and sources.
• Registering downstream dashboards/apps as exposures for lineage.
• Setting up dbt docs generation and reusable doc blocks.
• Do NOT use for writing tests (use testing-dbt-projects).

Workflow

- [ ] Describe each model: what it is, its grain, and who uses it
- [ ] Describe key columns (keys, enums, money, dates)
- [ ] Reuse repeated definitions with doc blocks
- [ ] Register BI dashboards as exposures
- [ ] Run dbt docs generate and review lineage

1. Model description states the grain and purpose in one or two lines — the grain is the most valuable fact for a consumer.
2. Column descriptions for keys, enums, money, and dates; skip self-evident ones to avoid noise.
3. Doc blocks ({% docs %}) for definitions reused across models (e.g. what "active customer" means) so they stay consistent.
4. Exposures connect models to the dashboards/ML jobs that consume them, so lineage and dbt build --select +exposure work.

Patterns

schema.yml with descriptions:

models:
  - name: fct_orders
    description: "One row per order line. Grain: order_id + line_number. Feeds Finance revenue dashboard."
    columns:
      - name: order_id
        description: "Natural order identifier from the shop system."
      - name: status
        description: '{{ doc("order_status") }}'

Reusable doc block (in a .md file under models/):

{% docs order_status %}
Lifecycle status: placed → shipped → delivered, or cancelled at any point.
{% enddocs %}

Exposure:

exposures:
  - name: revenue_dashboard
    type: dashboard
    maturity: high
    url: https://bi.example.com/revenue
    depends_on:
      - ref('fct_orders')
      - ref('dim_customer')
    owner: { name: Data Team, email: data@example.com }

Then dbt docs generate && dbt docs serve renders descriptions and a lineage graph including exposures.

Common pitfalls

• Restating the column name ("order_id is the order id") — add only what the name cannot convey (source, units, grain, meaning of enum values).
• Omitting the grain — the single most useful line for any consumer.
• Duplicating definitions across models instead of using a doc block — they drift apart.
• No exposures — lineage stops at the warehouse and you cannot see what breaks downstream when a model changes.