title: Implementation of having [0,2] rows, but not more, with similar data
body: <p>I am implementing an access database, using MS Access 2016. I am trying to create a table that has some columns, where 2 of them are a combined foreign key.</p>
  
  <p>Now, I want each value of the foreign key to be usable a maximum of <strong>2 times</strong>, in the new table. If a user tries to use the same value, a third time, then the program should give an error.</p>
  
  <p>I haven't been able to find an answer to this question anywhere else.</p>
  
  <pre><code>Original table: Field1  Field2
                    1        2
                    2        2
  New table: Field1(FK) Field2(FK)PK Field3 PK
                1         2            3
                1         2            4
                1         2            5      &lt;---- Generate error
  </code></pre>
  
  <p>FK - Foreign Key</p>
  
  <p>PK - Primary Key </p>
  
  <p><strong>EDIT1:</strong> I want to clarify that I want <strong>Field1</strong> and <strong>Field2</strong> in <strong>New Table</strong> to have the required functionality.</p>
  
  <p><strong>EDIT2:</strong> To give an example of my problem, I have a basketball game (Field1: StartingTime Field2: Stadium). For this game, I need 2 teams. Therefore I have a table GameTeams. But there cannot be more than 2 teams, thus I need this limitation of 2. In other words, each Game has 2 Gameteams. Hopefully this gives a better understanding. </p>