I'm trying to take my knowledge to the next level...or maybe it's still the introductory level, I'm not sure any more :)
I'd like to create a main fact table that lists all the students at a specific school, let's say there's 500 of them. From that, I'd like to create/link secondary fact tables that contain information about some, but not necessarily all, of the students. What I'm needing though, is for all 500 students to appear, even if the secondary fact tables that link up to do not contain information for a student. Let's say there is a test table, and only 200 of the students have taken a test. I want to see all 500 students listed, with the test information for the 200 students that have taken the test. Let's say there's another fact table, absences, and currently 300 students have at least one absence. Now I'd like to see all 500 students listed, with the 200 students that have test info and the 300 students that have absences.
Everything I've tried wants to "tighten" the filtering so that only students that have related data across all three of these facts table show. I keep seeing the "many to many" relationship under the Dimension Usage tab, but when I select it, it doesn't show anything to connect. All of these tables currently have at least one field in common, and that's the personID field. Is that not enough? Am I even on the right track? Is there a better way to tackle this?