title: Power BI can't establish a one-to-one relationship, cardinality issue
body: <p>I've got an issue with establishing relationships in Power Bi that I can't seem to solve. I've got two tables, Table 1 and Table 2. Table 1 has a column "Consignment ID" and Table 2 has a column "Consignment number". </p>
  
  <p>The column "Consignment ID" will have a big list of numbers and "Consignment number" will have a smaller list, all of which should match with a corresponding number in "Consignment ID". Therefore, I would like to establish a One-to-One relationship between these two columns and then use this relationship to extract the matching numbers from the "Consignment ID" column. However, Power BI is telling me that the "cardinality isn't valid for that relationship". I'm not sure why that is and I have no idea how to solve this problem. </p>
  
  <p>Does anyone have any thoughts on how to do that? </p>
  
  <p>Thank you for your support! </p>