Forum Discussion
Data Modeling and Star Schema
I have 7 tables for analyzing school grades. I want to use a star schema, but it doesn't look like a star. I'm thinking about combining the teachers, subjects and classes into the class dimension table. Is that a good idea? Also, I get an error message saying 'cyclic reference is not allowed' when I try to connect the dimTerm table to both the student table and the fact table. How can I fix this? Do you have any recommendations for my data model?
Oliver2024 once you remove relationship between dimterm and dimclasses, it will allow you to make relationship between dimclasses and factsturdentresults to be active (it is inactive now), and that would be the correct approach.
Only other part is that dimteacher and dimsubjects are related to dimclasses and that is making it a snowflake schema. In the ideal world these two tables will have direct relationship with fact table but seems like that is not possible.
3 Replies
Oliver2024 Yes, that sounds like a good idea. I would then connect DimTerms to your DimClasses table. Bit of a snowflake at that point but probably the right way to go.
Is it better to remove the link between DimTerms and DimClasses because FactStudentResults is already linked to DimTerms?
Oliver2024 once you remove relationship between dimterm and dimclasses, it will allow you to make relationship between dimclasses and factsturdentresults to be active (it is inactive now), and that would be the correct approach.
Only other part is that dimteacher and dimsubjects are related to dimclasses and that is making it a snowflake schema. In the ideal world these two tables will have direct relationship with fact table but seems like that is not possible.
