How it Works

The expect_table_columns_to_match_ordered_list test from the dbt-expectations package asserts that a table's columns match a specified list exactly — both in name and in order. This is particularly useful for tables consumed by external systems or tools that depend on a fixed column position (e.g., CSV exports, BI connectors, or legacy pipelines).

An optional transform argument (e.g., lower) enables case-insensitive comparison.

Steps and Conditions

1. Define Ordered Column List: Provide the expected column names in the exact required order.

2. Optional Transform: Apply lower or other transforms for case-insensitive matching.

3. Execution: The table's actual column order is compared against the expected list.

4. Outcome: Pass if columns match the list exactly in order and name; fail otherwise.

Example Usage: Data Export Pipeline

A financial reporting team exports a monthly_summary model to a third-party tool that relies on fixed column positions. They want to enforce that the column order never changes.

models:
  - name: monthly_summary
    tests:
      - dbt_expectations.expect_table_columns_to_match_ordered_list:
          column_list: ["month", "revenue", "expenses", "net_profit", "region"]
          transform

models:
  - name: monthly_summary
    tests:
      - dbt_expectations.expect_table_columns_to_match_ordered_list:
          column_list: ["month", "revenue", "expenses", "net_profit", "region"]
          transform

models:
  - name: monthly_summary
    tests:
      - dbt_expectations.expect_table_columns_to_match_ordered_list:
          column_list: ["month", "revenue", "expenses", "net_profit", "region"]
          transform

This prevents silent data misalignment in the downstream tool caused by column reordering.