Adds the specified data-relation definition to the ProDataGraphMetaData object.

You can only call this method after you have already called the addTable() method to define the ProDataObject collections that participate in the specified data-relation. You must also call this method to define each required data-relation before attaching this ProDataGraphMetaData object to the ProDataGraph. This method throws an Exception if any table participating in the specified data-relation is not already a member of the ProDataGraphMetaData.