How to design student quarterly registration fact table

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How to design student quarterly registration fact table

Post  dianaantova on Wed May 06, 2009 2:04 pm

I am in the process of creating a student data warehouse for a university. I want to track the student quarterly registration. I am wondering what the best way to create the fact table is. The main dimensions should be time (quarter) and student but there are a lot of attributes that are related to the quarterly student record - like registration status, fee status, level, disciplinary status, etc – about 30 of them. Do I include them all in the fact table or do they belong to a separate dimension? If I put them in a dimension then it needs to include the same keys as the fact table – student id, time period.
Thank you for your help,
Diana

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Re: How to design student quarterly registration fact table

Post  BoxesAndLines on Thu May 07, 2009 6:46 pm

Those attributes belong in a separate dimension.
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Re: How to design student quarterly registration fact table

Post  VHF on Mon May 11, 2009 5:10 pm

You could make a 'student status' profile dimension. This dimension would contain the attributes related to student status. It would not be keyed by student id or time period. Rather, there would be a record (with a surrogate key) for each combination of attribute values*. Each student registration fact record would then point to the surrogate key for the profile dimension record that contains the combination of attributes that currently describes that student’s status.

*With 30 attributes, creating one record for each possible combination of attributes would result in an impossibly large profile dimension with billions of rows. Instead, create records as needed only for the combinations of attributes that exist. The maximum number of rows in the dimension would then be the number of students times the number of periods worth of history in the data warehouse. You could also break the attributes down into smaller groups and create more than one profile dimension.

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Re: How to design student quarterly registration fact table

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