Cannot save Links in Database Export
I am using Crystal Reports 2013. I just add a an additional table in my report and I tried to establish a link to the new table. I saved it but everytime the link I saved has disappeared. My question is :
1. Can I only establish link using primary key or secondary key in the link?
2. If I tried to establish link between 2 tables but the field is not part of the key, is there any way I can establish the link?
3. When I saved my link. Crystal Reports never given me any error. So I though the link I established is ok. But it disappeared everytime I check back. If I can not establish link without using key, then Crystal Reports should have error message appears and warn me.
Any idea of how to fix this problem?