title: ConstraintException when filling a DataGridView from a SQL Server view
body: <p>I have a SQL Server view which does a simple join of two tables and returns some of the columns. Running this view in Management Studio does not cause any problems, the expected data (two rows) is returned.</p>
  
  <p>When I use this view as data source for my TableAdapter in Visual Studio, I get a ConstraintException saying "Failed to enable constraints. One or more rows contain values violating non-null, unique, or foreign-key constraints.". </p>
  
  <p>I used EnforceConstraints = false before calling tableAdapter.Fill( dataSet.vwMyView ), so I could get some more information about the cause of this problem. I ended up with a message saying that the column "MyColumn" has a constraint that it must be unique, but the value 4 (an id) already exists (yes, there are two rows with this id).</p>
  
  <p>I do understand that this particular is unique (and the primary key) in one of the two tables I join in my view, however, I do not get why this should cause an error in my DataGridView because </p>
  
  <ul>
  <li>I only want to display data</li>
  <li>I do not get any errors when executing the same select on the very same view in Management Studio</li>
  </ul>
  
  <p>Why is that? I need to display the id value, and I also do not understand why I actually get that error.</p>
  
  <p>Thanks in advance &amp;</p>
  
  <p>Best regards</p>
  
  <p>Gorgsenegger</p>