Final submission for Assignment 2 (ER diagrams, SQL script, md file)

[tanveerrouf]

What changes are you trying to make? (e.g. Adding or removing code, refactoring existing code, adding reports)

Added the final Assignment2.md with my written responses for Sections 1 & 4.
Committed the two ER‑diagram images required by Prompt 1 & 2.
Added the assignment2.sql script that contains all the SQL tasks (COALESCE, window functions, string ops, UNION, CROSS JOIN, INSERT/DELETE/UPDATE, etc.).

What did you learn from the changes you have made?

How to design a clean logical data model for a small bookstore and extend it with shift and address tables.
The practical difference between SCD Type 1 (overwrite) and SCD Type 2 (historical) when versioning the CUSTOMER_ADDRESS table.
Real‑world use of window functions (ROW_NUMBER(), DENSE_RANK()) and COALESCE for cleaning nulls.

Was there another approach you were thinking about making? If so, what approach(es) were you thinking of?

I considered using a separate “address_history” table instead of SCD Type 2, but the assignment explicitly asked for the classic Type 2 design (surrogate key + effective dates).

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

Challenge was that my first push failed because GitHub no longer accepts password authentication.
Solution: Generated a Personal Access Token (repo scope), cleared the old cached credentials, and re‑pushed using the token as the password.

How were these changes tested?

Ran git status after each add to verify only the four required files were staged.
Executed the .sql script in DB Browser for SQLite; all queries returned expected results (no syntax errors, correct row counts).
Opened the assignment-two branch on GitHub to confirm the markdown, diagrams, and script appear correctly.

A reference to a related issue in your repository (if applicable)

NA

Checklist

• [Y] I can confirm that my changes are working as intended

[khsergvl]

Thank you for submitting assignment 2.
Mark: 70/70