Columns do not have unique values

[sabah khalid]

Dear all,

I have this error message:

An unhandled exception of type 'System.ArgumentException' occurred in system.data.dll

Additional information: These columns don't currently have unique values.

This occurs when loading a mysql DB into vb.net as a treeview structure. I have been working on this problem for a while and it is driving me mad.

I have 4 tables in mysql. A parent, child1 and child 2 table and a relation table that ties the three tables together. The primary id's in parent, child1 and child2 are foreign keys in the relation table. I am loading them into a vb.net software.

The relation table is the problem. It contains the id's from parent, child1 and child2. The parent id's can be duplicated, BUT the child1 id's and child2 id's cannot, even though they are set as foreign keys.

so i cannot have:

parent id child1 id child2 id
1 2 1
1 2 2
1 2 2

HELP!! any ideas?

Thanks in advance