Doc blocks for reusable descriptions in dbt - Practice Problems & Coding Challenges

Challenge - 5 Problems

🧠 Conceptual

intermediate

Understanding the purpose of doc blocks in dbt

What is the main purpose of using doc blocks in dbt projects?

A To create reusable documentation snippets that can be referenced across models and sources

B To define SQL queries that run before the main model executes

C To write test cases for data quality checks

D To store configuration settings for dbt profiles

💡 Hint

Think about how documentation can be reused efficiently in multiple places.

Doc blocks in dbt allow you to write documentation once and reuse it in multiple models or sources, ensuring consistency and saving time.

❓ Predict Output

intermediate

Output of referencing a doc block in a model description

Given the following doc block and model configuration, what will be the final description of the model?

docs:
  - name: customer_description
    description: "Contains customer demographic information"

models:
  - name: customers
    description: "{{ doc('customer_description') }}"

A Contains customer demographic information

B {{ doc('customer_description') }}

C Error: doc block not found

D No description available

💡 Hint

Remember how doc blocks are referenced inside model descriptions.

The {{ doc('customer_description') }} syntax injects the content of the doc block named customer_description into the model's description.

❓ data_output

advanced

Result of rendering multiple doc blocks in a source description

Consider these doc blocks and a source configuration:

docs:
  - name: source_name_desc
    description: "Source system name"
  - name: source_table_desc
    description: "Table containing sales data"

sources:
  - name: sales_source
    description: "{{ doc('source_name_desc') }} - {{ doc('source_table_desc') }}"

What is the final description of the source sales_source after rendering?

A {{ doc('source_name_desc') }} - {{ doc('source_table_desc') }}

B Source system name - Table containing sales data

C Source system name Table containing sales data

D Error: Cannot concatenate doc blocks

💡 Hint

Check how multiple doc blocks are combined in a string.

Each {{ doc('...') }} is replaced by its description, and the string concatenates them with ' - ' in between.

🔧 Debug

advanced

Identifying the error in doc block usage

What error will occur when running dbt with this model configuration?

models:
  - name: orders
    description: "{{ doc('non_existent_doc') }}"

A Model runs successfully with empty description

B Runtime error: Undefined variable 'non_existent_doc'

C Compilation error: doc block 'non_existent_doc' not found

D Syntax error in model configuration

💡 Hint

What happens if you reference a doc block that does not exist?

dbt raises a compilation error if a referenced doc block is missing, preventing the model from running.

🚀 Application

expert

Creating a reusable doc block for column descriptions

You want to create a reusable doc block for a column named customer_id used in multiple models. Which of the following dbt YAML snippets correctly defines and references this doc block in a model's column description?

A

models:
  - name: orders
    columns:
      - name: customer_id
        description: "{{ docs('customer_id_desc') }}"

B

models:
  - name: orders
    columns:
      - name: customer_id
        description: "Unique identifier for each customer"

docs:
  - name: customer_id_desc
    description: "{{ doc('customer_id_desc') }}"

C

docs:
  - name: customer_id_desc
    description: "Unique identifier for each customer"

models:
  - name: orders
    columns:
      - name: customer_id
        description: "customer_id_desc"

D

docs:
  - name: customer_id_desc
    description: "Unique identifier for each customer"

models:
  - name: orders
    columns:
      - name: customer_id
        description: "{{ doc('customer_id_desc') }}"

💡 Hint

Check the correct syntax for defining and referencing doc blocks in column descriptions.

Doc blocks are defined under docs with a name and description. They are referenced in model columns using {{ doc('name') }}. Option D follows this pattern correctly.