Multiple fact tables / directions of relations

[DanielB_NL]

Hi all, 

I'm not really sure what to state as topic, because this I'm not really sure what technique I'm looking for. Let me describe the problem:

• I have projects and the material that is needed to complete these projects are described in multiple lines of the table project_article. 
• The purchase of these articles is done in the tables Purchase_receipt  and Purchase_receipt_lines: the last one has per article multiple rows with purchase info
• So each row in the table Project_article has an acticle_code, this also goes for the table Purchase_receipt_line
• I want to know for each row in project_arctice when I can expect the first delivery of this article: on the purchase receipt line there is a field Order_confirmation_date.
• I not only want the earliest date for this article_code but also the expected amount. This would be the field Amount_open.

When I make a relation between both tables on the field article_code, I get a many-to-many relation. If I use the table Article  between it, the direction is not good, but I don't know how to fix this. Can someone tell me how to do this? Thanks in advance for the reply!