dbt-no-select-star

This dbt package contains a macro that will throw an error if you attempt to use select * in your model. This macro effectively forces you to be explicit about the columns you want to select.

Installation

Adding this package to your project will enable the macro. To install, add the following to your packages.yml file:

packages:
  - git: "https://github.com/patricktrainer/dbt-no-select-star.git"
    revision: 0.1.0

Usage

To use the macro, simply add the following at the end of your model:

{{ no_select_star() }}

For example:

select 
  my_column,
  my_other_column,
  {{ no_select_star() }}
from {{ ref(my_table) }}

This will throw an error if you attempt to use select * in your model.

The error message will look like this:

'DONT SELECT * FROM THIS TABLE!!!1'

To avoid the error, be explicit about the columns you want to select:

select 
  my_column,
  my_other_column
from {{ ref(my_table) }}

How does this work?

This works by leveraging computed columns. Computed columns are a feature that allow you to create a column that is the result of a SQL expression. If you inspect the macro, you'll notice that it creates a string typed column. This column is then cast as a char() type with a length of 1 byte. Obviously, the string "DONT SELECT * FROM THIS TABLE!!!1" is longer than 1 byte, so the cast will fail. This will cause the query to fail, and the error message will be displayed.