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Testing Columns

Column tests are meant to check for null and unique values, and are always run after transformations. This cannot be changed unless using a user-defined node.

Example Column Test​

  1. Click on Testing → Column.

  2. Select both Unique and Null.

    Example column test

  3. Now click on Null next to C_NATIONKEY. This will check to ensure all entries for this column are populated (not null).

  4. Run the node and it should succeed, as there's no null entries.

    Successful column test

  5. Now try also selecting Unique for the C_NATIONKEY column. This will check to ensure all entries for this column are unique.

  6. Run the node and it will fail, as C_NATIONKEY has repeated entries. Notice that the data was still processed, as column tests will always continue on failure.

Failed column test

Viewing Column Level Tests​

After Create and Run you Nodes, you can see if the test passed or failed in the Results view.

The following image shows an example of a passing and failing test.

  • The Node level test Length is less than 0 is failing.
  • The column level test N_NATIONKEY: UNIQUE is passing.
  • The column level test N_REGIONKEY: UNIQUE is failing.
Data management interface showing STG_NATION table with fields N_NATIONKEY, N_NAME, and N_REGIONKEY. Test validation results include failures for 'Length is less than 0' and uniqueness tests for N_NATIONKEY and N_REGIONKEY. The interface displays nation data defined by TPC-H with options to validate, create and run tests.
info

You can also see column and Node level test failures as part of Refresh Results.