dbt with Teradata Vantage
This tutorial demonstrates how to use dbt (Data Build Tool) with Teradata Vantage. It’s based on the original dbt Jaffle Shop tutorial. A couple of models have been adjusted to the SQL dialect supported by Vantage.
Access to a Teradata Vantage instance.
If you need a test instance of Vantage, you can provision one for free at https://clearscape.teradata.com.
Python 3.7, 3.8, 3.9, 3.10 or 3.11 installed.
Clone the tutorial repository and cd into the project directory:
git clone https://github.com/Teradata/jaffle_shop-dev.git jaffle_shop cd jaffle_shop
Create a new python environment to manage dbt and its dependencies. Activate the environment:
dbt-teradatamodule and its dependencies. The core dbt module is included as a dependency so you don’t have to install it separately:
pip install dbt-teradata
We will now configure dbt to connect to your Vantage database. Create file
$HOME/.dbt/profiles.yml with the following content. Adjust
<password> to match your Teradata instance.
The following dbt profile points to a database called
Now, that we have the profile file in place, we can validate the setup:
If the debug command returned errors, you likely have an issue with the content of
jaffle_shop is a fictional e-commerce store. This dbt project transforms raw data from an app database into a dimensional model with customer and order data ready for analytics.
The raw data from the app consists of customers, orders, and payments, with the following entity-relationship diagram:
dbt takes these raw data table and builds the following dimensional model, which is more suitable for analytics tools:
In real life, we will be getting raw data from platforms like Segment, Stitch, Fivetran or another ETL tool. In our case, we will use dbt’s
seed functionality to create tables from csv files. The csv files are located in
./data directory. Each csv file will produce one table. dbt will inspect the files and do type inference to decide what data types to use for columns.
Let’s create the raw data tables:
You should now see 3 tables in your
raw_payments. The tables should be populated with data from the csv files.
Now that we have the raw tables, we can instruct dbt to create the dimensional model:
So what exactly happened here? dbt created additional tables using
CREATE TABLE/VIEW FROM SELECT SQL. In the first transformation, dbt took raw tables and built denormalized join tables called
customer_payments. You will find the definitions of these tables in
In the second step, dbt created
fct_orders tables. These are the dimensional model tables that we want to expose to our BI tool.
dbt applied multiple transformations to our data. How can we ensure that the data in the dimensional model is correct? dbt allows us to define and execute tests against the data. The tests are defined in
./marts/core/schema.yml. The file describes each column in all relationships. Each column can have multiple tests configured under
tests key. For example, we expect that
fct_orders.order_id column will contain unique, non-null values. To validate that the data in the produced tables satisfies the test conditions run:
Our model consists of just a few tables. Imagine a scenario where where we have many more sources of data and a much more complex dimensional model. We could also have an intermediate zone between the raw data and the dimensional model that follows the Data Vault 2.0 principles. Would it not be useful, if we had the inputs, transformations and outputs documented somehow? dbt allows us to generate documentation from its configuration files:
dbt docs generate
This will produce html files in
You can start your own server to browse the documentation. The following command will start a server and open up a browser tab with the docs' landing page:
dbt docs serve
This tutorial demonstrated how to use dbt with Teradata Vantage. The sample project takes raw data and produces a dimensional data mart. We used multiple dbt commands to populate tables from csv files (
dbt seed), create models (
dbt run), test the data (
dbt test), and generate and serve model documentation (
dbt docs generate,
dbt docs serve).