[mouweili]

What changes are you trying to make?

I completed Assignment 2: designed a bookstore logical model (with and without employee shifts), answered the Type 1 vs Type 2 slowly changing dimension prompt, wrote the SQL for Sections 2 and 3 in assignment2.sql, and wrote the Section 4 ethics response in Assignment2.md. This branch was created from assignment-one, so the Assignment 1 files also appear in the diff.

What did you learn from the changes you have made?

I learned how to use COALESCE, window functions, string functions, UNION, CROSS JOIN, and INSERT/DELETE/UPDATE, and how to design a model with a date table and slowly changing dimensions.

Was there another approach you were thinking about making?

For the most recent visit query, I considered ROW_NUMBER versus DENSE_RANK. I used DENSE_RANK so multiple purchases on the same market date share the same visit number.

Were there any challenges? If so, what issue(s) did you face? How did you overcome it?

Keeping each query separate and handling tables that already existed when re-running statements. I fixed these by testing queries one at a time.

How were these changes tested?

I ran each query in DB Browser for SQLite and checked row counts and column values.

Checklist

• I can confirm that my changes are working as intended

[github-actions]

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