Feature to add _n alias to same column names #3147

[techytushar]

Signed-off-by: Tushar Mittal [email protected]

resolves #3147

Description

Checklist

• I have signed the CLA
• I have run this code in development and it appears to resolve the stated issue
• This PR includes tests, or tests are not required/relevant for this PR
• I have updated the CHANGELOG.md and added information about my change to the "dbt next" section.

[jtcohen6]

Thanks for picking this up @techytushar, this is awesome! I took this for a spin locally, and it resolves both of the reproduction cases mentioned in #3147 (calling run_query() in a file, and the original RPC request).

• Could you add a test? I think a unit test is sufficient, passing multiple columns with the same name to process_results() and checking that all columns are present before and after.
• Could you add yourself to the list of contributors?

I'll also tag one of the folks from the Core team for python review. In particular, I'd like to know if a loop-based approach would have meaningful performance implications at scale.

[gshank]

I think the performance implications are trivial, and the fix looks good to me.

[techytushar]

Hi @jtcohen6 , thank you for the review. In the unit tests folder there are lot of files, please can you tell in which one should I add the test? Also I am unable to find the list of contributors, can you guide me in this as well 🙂

[jtcohen6]

@techytushar Good call! It doesn't look like any of the existing unit test files have related coverage, so I think a new unit test file makes sense—something like unit/test_sql_result.py. Here's what I'm envisioning as the basic setup:

import unittest
from dbt.adapters.sql.connections import SQLConnectionManager

class TestProcessSQLResult(unittest.TestCase):
    def test_duplicated_columns(self):
        cols_with_one_dupe = ['a', 'b', 'a', 'd']
        rows = [(1, 2, 3, 4)]

        self.assertEqual(
            SQLConnectionManager.process_results(cols_with_dupe, rows),
            [{"a": 1, "b": 2, "a_2": 3, "d": 4}]
        )
        
        cols_with_more_dupes = ['a', 'a', 'a']
        
        ... more test cases ...

There's also a code style error from flake8, once fixed the rest of the CI suite will run:

core/dbt/adapters/sql/connections.py:107:80: E501 line too long (81 > 79 characters)

The Contributors section is just a few lines further down in the Changelog here.

Let me know if you have more questions, happy to help!

[kwigley]

looks good 👍 thanks for the contribution

[jtcohen6]

Thanks for this @techytushar!