title: How to make a existing column "unique" in PowerBI, so I can form a "one-to-many" relationsship?
body: <p>I have 40 tables. One table has 20 rows, and one of the columns have 1385 distinct values.
  I would like to use this in a relationship with another table. </p>
  
  <blockquote>
    <p>TableName(1385 rows) Column:Name:(1385 distinct values)</p>
  </blockquote>
  
  <p>But when I try to do this in Powerbi/Manage-Relations, it will only accept the option "Many-to-Many" relationship. It reports that none of the column are "Unique".</p>
  
  <p>Well, the data in the column is unique. So how can I configure this column to be unique so I can use it in a "One-to-Many" relationship"?</p>
  
  <p>Do I have to edit the DAX expression and put the "DISTINCT" keyword in the expression for that column? And How?</p>
  
  <p>Now I have:</p>
  
  <pre><code>    }, {"Columnname", Int64.Type}, {
  </code></pre>