Column descriptions in dbt - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to add a description to the column customer_id in a dbt model.

dbt

columns:
  - name: customer_id
    description: "[1]"

Drag options to blanks, or click blank then click option'

ANumber of items purchased

BThe total sales amount

CDate of the transaction

DUnique identifier for each customer

Attempts:

3 left

💡 Hint

Common Mistakes

Using a description that does not match the column name

Leaving the description empty

The description field should explain what the column customer_id represents. Here, it is the unique identifier for each customer.

2fill in blank

medium

Complete the code to add a description for the order_date column in a dbt model.

dbt

columns:
  - name: order_date
    description: "[1]"

Drag options to blanks, or click blank then click option'

ANumber of products in the order

BDate when the order was placed

CTotal price of the order

DCustomer's unique ID

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing order_date with customer ID or price

Writing a vague description

The order_date column stores the date when the order was placed, so the description should reflect that.

3fill in blank

hard

Fix the error in the column description for total_amount by selecting the correct description.

dbt

columns:
  - name: total_amount
    description: "[1]"

Drag options to blanks, or click blank then click option'

ATotal amount of the order in USD

BDate of the transaction

CUnique customer identifier

DNumber of items sold

Attempts:

3 left

💡 Hint

Common Mistakes

Using descriptions related to date or customer ID

Not specifying the currency or total nature

The total_amount column should describe the total value of the order, usually in a currency like USD.

4fill in blank

hard

Fill both blanks to add descriptions for product_id and quantity columns in a dbt model.

dbt

columns:
  - name: product_id
    description: "[1]"
  - name: quantity
    description: "[2]"

Drag options to blanks, or click blank then click option'

AUnique identifier for each product

BNumber of units ordered

CDate when the product was added

DPrice per unit of the product

Attempts:

3 left

💡 Hint

Common Mistakes

Mixing up descriptions between product and quantity

Using unrelated descriptions

product_id is the unique ID for products, and quantity is the number of units ordered.

5fill in blank

hard

Fill all three blanks to add descriptions for user_id, signup_date, and is_active columns in a dbt model.

dbt

columns:
  - name: user_id
    description: "[1]"
  - name: signup_date
    description: "[2]"
  - name: is_active
    description: "[3]"

Drag options to blanks, or click blank then click option'

AUnique identifier for each user

BDate when the user signed up

CIndicates if the user account is active

DTotal number of user logins

Attempts:

3 left

💡 Hint

Common Mistakes

Confusing is_active with login counts

Using vague or incorrect descriptions

user_id is the unique user ID, signup_date is when the user joined, and is_active shows if the account is currently active.

Practice

1. What is the main purpose of adding column descriptions in dbt?

easy

A. To change the data type of columns

B. To create new columns in the model

C. To explain what each column means for better understanding

D. To write SQL queries inside the YAML file

Solution

1. Step 1: Understand the role of column descriptions

   Column descriptions provide explanations about what each column represents in the data model.

2. Step 2: Differentiate from other YAML uses

   They do not change data types, create columns, or contain SQL code; they only describe columns.

3. Final Answer:

   To explain what each column means for better understanding -> Option C

4. Quick Check:

   Column descriptions = explain columns [OK]

Hint: Descriptions explain columns, not change data or structure [OK]

Common Mistakes:

• Thinking descriptions change data types
• Confusing descriptions with SQL code
• Assuming descriptions create new columns

2. Which of the following is the correct syntax to add a column description in a dbt YAML file?

easy

A. description:
customer_id: 'Unique ID for each customer'

B. columns:
- name: customer_id
description: 'Unique ID for each customer'

C. columns:
customer_id: 'Unique ID for each customer'

D. columns:
- customer_id: 'Unique ID for each customer'

Solution

1. Step 1: Recall YAML structure for columns in dbt

   The correct format uses a list under columns: with each item having name and description keys.

2. Step 2: Compare options to correct format

   columns: - name: customer_id description: 'Unique ID for each customer' matches the correct YAML syntax with dash, name, and description keys properly indented.

3. Final Answer:

   columns: - name: customer_id description: 'Unique ID for each customer' -> Option B

4. Quick Check:

   YAML columns list with name and description = columns: - name: customer_id description: 'Unique ID for each customer' [OK]

Hint: Use dash list with name and description keys in YAML [OK]

Common Mistakes:

• Using key-value pairs without dash list
• Putting description outside columns section
• Incorrect indentation or missing name key

3. Given this YAML snippet in a dbt model:

columns:
  - name: order_id
    description: 'Unique order identifier'
  - name: order_date
    description: 'Date when order was placed'

What will dbt show for the order_date column in documentation?

medium

A. No description available

B. Unique order identifier

C. order_date

D. Date when order was placed

Solution

1. Step 1: Locate the description for order_date

   The YAML shows order_date has description 'Date when order was placed'.

2. Step 2: Understand dbt documentation behavior

   dbt uses the description text to show in docs, not the column name or other text.

3. Final Answer:

   Date when order was placed -> Option D

4. Quick Check:

   dbt docs show column description text [OK]

Hint: dbt docs show the description text, not column name [OK]

Common Mistakes:

• Confusing column name with description
• Assuming no description if present
• Picking wrong description text

4. You wrote this YAML for column descriptions but dbt docs shows no descriptions:

columns:
  - name: user_id
    description 'User unique ID'

What is the error causing descriptions not to appear?

medium

A. Missing colon after description key

B. Wrong indentation of columns

C. Missing dash before name

D. Description text should be uppercase

Solution

1. Step 1: Check YAML syntax for description key

   The line description 'User unique ID' is missing a colon after description.

2. Step 2: Understand YAML parsing impact

   Without the colon, YAML is invalid and dbt cannot read the description, so docs show no description.

3. Final Answer:

   Missing colon after description key -> Option A

4. Quick Check:

   YAML keys need colon after them [OK]

Hint: Always put colon after YAML keys like description [OK]

Common Mistakes:

• Forgetting colon after keys
• Incorrect indentation
• Assuming case sensitivity matters

5. You want to add descriptions for multiple columns in a dbt model YAML file. Which approach correctly documents two columns product_id and price with descriptions, ensuring dbt docs will display them properly?

hard

A. columns:
- name: product_id
description: 'ID of the product'
- name: price
description: 'Price in USD'

B. columns:
product_id: 'ID of the product'
price: 'Price in USD'

C. columns:
- product_id: 'ID of the product'
- price: 'Price in USD'

D. columns:
name: product_id
description: 'ID of the product'
name: price
description: 'Price in USD'

Solution

1. Step 1: Recall correct YAML list format for multiple columns

   Each column must be an item in a list with name and description keys.

2. Step 2: Evaluate each option's structure

   columns: - name: product_id description: 'ID of the product' - name: price description: 'Price in USD' correctly uses a list with two items, each having name and description properly indented.

3. Final Answer:

   columns: - name: product_id description: 'ID of the product' - name: price description: 'Price in USD' -> Option A

4. Quick Check:

   List of columns with name and description keys = columns: - name: product_id description: 'ID of the product' - name: price description: 'Price in USD' [OK]

Hint: Use dash list with name and description for each column [OK]

Common Mistakes:

• Using key-value pairs without dash list
• Repeating keys without list items
• Incorrect indentation breaking YAML