Is it possible to have an association mapping a table to itself?
Table: ConditionId ConditionName ... ... ParentConditionId
where we can have many ParentConditionIds each mapping to the same ConditionId.
I've tried a one to many mapping but I'm getting an error when there is no children.
Yes it is possible. Put the FK in your database and the wizard will map it correctly. Make sure ParentConditionId is nullable.