DBT DBT Macros & Jinja 2

Question 1

Which dbt macro is used to generate a cross-database compatible date-trunc expression?

Accepted Answer

dbt.date_trunc()

Answer

`dbt.date_trunc(datepart, date)` is a built-in cross-database macro that adapts the date_trunc SQL function for each supported adapter.

Question 2

What does the `var()` function do in a dbt model?

Accepted Answer

Reads a project variable defined in dbt_project.yml or passed via --vars

Answer

`{{ var('name', default) }}` reads variables from the `vars:` section of dbt_project.yml or those overridden at runtime with `--vars`.

Question 3

How do you pass a runtime variable override when running dbt?

Accepted Answer

dbt run --vars '{key: value}'

Answer

The `--vars` flag accepts a YAML dictionary string that overrides project variables for the duration of the run.

Question 4

What Jinja construct lets you loop over a list and generate repeated SQL fragments in dbt?

Accepted Answer

{% for item in list %} ... {% endfor %}

Answer

`{% for item in list %}...{% endfor %}` iterates over a list and renders the body for each element, enabling dynamic SQL generation.

Question 5

What is the purpose of `adapter.dispatch()` in dbt macros?

Accepted Answer

Finds the correct macro implementation for the active database adapter

Answer

`adapter.dispatch()` enables polymorphism by resolving a macro to its adapter-specific implementation (e.g., Snowflake vs BigQuery).

DBT - Certified Data Build Tool Developer Practice Test