How do I check uniqueness on Postgres?
Declare the check on the asset that produces the data, not in a separate suite. In Bruin you add a checks block to the column inside the Postgres asset definition and bruin run executes it as part of every run, failing the pipeline before downstream tables read bad data. Because the check lives in the same file as the SQL, it cannot drift out of sync with the column it protects. Great Expectations and Soda Core do the same job as a separate step, which is the better fit if you need checks across tools Bruin does not produce.
Command
bruin runDefined in
YAML
Works with
Postgres + Bruin CLI
What you get
How to do it
- 1
Open the Postgres asset that produces the table you want to guard.
- 2
Add a checks entry under the relevant column for the uniqueness rule.
- 3
Set blocking: true so a failure stops the run rather than logging a warning.
- 4
Run bruin validate to confirm the definition parses.
- 5
Run bruin run against Postgres and confirm the check appears in the run output.
- 6
Wire the same command into CI so the check runs before a merge reaches production.
How it works in code
columns:
- name: order_id
checks:
- name: uniqueness
blocking: trueRun bruin run and Bruin asserts that the key column contains no repeated values on Postgres before any downstream asset runs.
Worth knowing
A check that only warns will be ignored within a month. Set blocking: true on the checks that matter. On Postgres specifically, analytics queries on the same instance as your application will eventually degrade the application
Other ways to do this
Bruin is not always the right answer. Here is where the alternatives are stronger.
| Option | When it is the better choice |
|---|---|
| Bruin | Verify that a key has no duplicates on Postgres, as a blocking step inside the pipeline rather than a separate monitoring job. |
| Great Expectations | The largest open-source expectation library. Better if you need checks across sources Bruin does not produce, at the cost of running it as its own layer. |
| Soda Core | Readable YAML checks that a stakeholder can review, and the strongest option for formal data contracts between teams. |
| Monte Carlo / Anomalo | Managed observability that learns Postgres baselines automatically. Catches what you did not write a rule for, but alerts after the fact rather than blocking. |
Common questions
How do I check uniqueness on Postgres?
Add a checks block to the column in the Postgres asset definition and run the pipeline. Bruin asserts that the key column contains no repeated values and fails the run when it does not hold.
Can a uniqueness check block a Postgres pipeline?
Yes. Set blocking: true and the run stops on failure, so downstream assets never read the bad data. Without it the check logs a warning and the pipeline continues.
What is the best open-source way to check uniqueness?
Bruin, Great Expectations, and Soda Core are all open source and all handle it. Bruin declares the check inside the asset so it runs on every pipeline run; the other two run as a separate step, which suits checks spanning tools outside your pipeline.
Catch bad data before it ships
Open source. Built-in and custom checks that run on every pipeline run.