Materializations
Materializations, which determine how dbt stores and manages the results of your SQL transformations. Here lets look into ephemeral views and materialized views.
Ephemeral Views:
Definition:
Ephemeral views are temporary, on-the-fly representations of your transformed data. When using ephemeral materialization, dbt doesn’t persist the results to a physical table. Instead, it treats the transformation as a subquery, executing the SQL code dynamically whenever needed.
— Example of an ephemeral view
WITH transformed_data AS ( SELECT user_id, COUNT(*) AS transaction_count FROM raw_data GROUP BY user_id ) SELECT * FROM transformed_data;
Materialized Views:
Definition:
Materialized views, on the other hand, involve persisting the results of your transformations as physical tables in your database. This allows dbt to store the computed values, making them readily available for faster querying.
— Example of a materialized view
WITH transformed_data AS (
SELECT
user_id,
COUNT(*) AS transaction_count
FROM raw_data
GROUP BY user_id
)
SELECT *
FROM transformed_data
-- Materialize the results as a physical table named 'user_summary'
{% materialized %}
Choosing the Right Materialization:
Ephemeral for Flexibility:
Use ephemeral views when flexibility and real-time access to the latest data are paramount. It’s suitable for exploration, iterative analysis, or scenarios where the underlying data frequently changes.
Materialized for Performance:
Choose materialized views when optimizing query performance and ensuring consistent reporting are critical. Materializations are particularly effective for large datasets and complex transformations.
We at Helical have more than 10 years of experience in providing solutions and services in the domain of data and have served more than 85+ clients. We are also DBT partners, hence in case if you are looking for certain assistance, consulting, services please do reach out on nikhilesh@Helicaltech.com
Thank You
Nikitha Rastapuram
Helical IT Solutions