Data Modeling & Transformation Flashcards

Which function should be used to reference one dbt model from another so dbt builds the dependency graph?

Answer: ref()

ref() creates a node dependency and resolves to the correct relation per environment.

Where are `sources` declared so that source() can reference raw tables?

Answer: A YAML properties file under the sources key

Sources are defined in YAML files with a sources: block listing schemas and tables.

What is the main purpose of the `dbt source freshness` command?

Answer: Check whether source data was loaded within expected thresholds

Freshness compares a loaded_at_field against warn_after and error_after thresholds.

Which naming convention is commonly used for the first layer of models that lightly clean raw source data?

Answer: staging

Staging models, often prefixed stg_, rename, cast, and clean one source table each.

Why does dbt recommend selecting from sources only in staging models?

Answer: It centralizes source references so downstream models use ref() on cleaned data

Keeping source() calls in staging gives one place to adjust when raw tables change.

What does a Jinja `{% set %}` statement do in a dbt model?

Answer: Defines a variable for use within the template

set assigns a value to a Jinja variable that can be reused in the model.

Which file would you use to define a reusable SQL snippet called via {{ my_macro() }}?

Answer: A .sql file in the macros directory

Macros live in .sql files inside the macros directory, wrapped in {% macro %} blocks.