<p>I am trying to link two fields of a given table to the same field in another table.
I have done this before so I can't work out what is wrong this time.</p>

<p>Anyway:</p>

<pre><code>Table1
- Id (Primary)
- FK-Table2a (Nullable, foreign key relationship in DB to Table2.Id)
- FK-Table2b (Nullable, foreign key relationship in DB to Table2.Id)

Table2
- Id (Primary)
</code></pre>

<p>The association works for FK-Table2a but not FK-Table2b.
In fact, when I load into LINQ to SQL, it shows Table2.Id as associated to Table1.Id.
If I try and change this, or add a new association for FK-Table2b to Table2.Id it says: "Properties do not have matching types".</p>

<p>This also works in other projects - maybe I should just copy over the .dbml?</p>

<p>Any ideas?</p>

[{'answer_id': 45065, 'author': 'Matt Mitchell', 'author_id': 364, 'author_profile': 'https://Stackoverflow.com/users/364', 'pm_score': 3, 'selected': True, 'text': '<p>No idea on the cause, but I just reconstructed my .dbml from scratch and it fixed itself.\nOh for a "refresh" feature...</p>\n'}, {'answer_id': 1576158, 'author': 'Vildan', 'author_id': 191005, 'author_profile': 'https://Stackoverflow.com/users/191005', 'pm_score': 1, 'selected': False, 'text': '<p>I had the same problem. This error appeared when I tried to link different types of fields, or when I tryied to drag-and-drop table to .dbml space, but .dbml already had contained linked tables with different types of linked fields.</p>\n'}, {'answer_id': 1954376, 'author': 'DarenMay', 'author_id': 158833, 'author_profile': 'https://Stackoverflow.com/users/158833', 'pm_score': 2, 'selected': False, 'text': "<p>I see this problem when I try to create one-to-one relationships where one side of the relationship is nullable (so really, one-to-zero/one). LINQ-to-SQL doesn't seem to support this so it appears we are forced to a plural relationship and a collection that will contain zero or one items. Annoying.</p>\n"}]
['https://Stackoverflow.com/questions/45062', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/364/']