title: Relationship with primary and foreign key between 3 tables
body: <p>I would like to connect 3 tables. I can bring the first two tables in relationship, but the 3. table has already data, that is not identical with the contents from the other table. Because of that I couldn`t create a relationship with primary and foreign key.</p>
  <p>Is there any way to solve this problem?</p>
  <p>I am working on a project, I transfer data with API in our intern database , that is the reason, that one of the 3 tables is not empty.The transferred data must be saved in this partially filled table.</p>
  <p>I transfer the data between the tables using cursor.</p>