Assignment two

[HaroonV12]

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

I completed Assignment 2 by adding the required advanced SQL queries, including COALESCE, window functions, string manipulation, UNION, CROSS JOIN, INSERT, DELETE, and UPDATE queries. I also completed the required logical data models and written responses for Section 1.

What did you learn from the changes you have made?

I learned how to use more advanced SQL techniques, particularly window functions using ROW_NUMBER(), RANK(), PARTITION BY, and OVER. I also learned how to handle NULL values using COALESCE, manipulate strings using functions such as SUBSTR, INSTR, and TRIM, and combine results using UNION and CROSS JOIN.

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

Some of the queries could be completed using different approaches, such as temporary tables instead of subqueries or CTEs. For the window functions, I also considered using DENSE_RANK() instead of selecting distinct customer visit dates and applying ROW_NUMBER().

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

One challenge was working with queries that modify the database, particularly creating and updating the product_units table. I also had to make sure that the correct records were selected when using DELETE and UPDATE. I overcame these issues by testing each query individually in DB Browser for SQLite and checking the results before moving on to the next query.

How were these changes tested?

I tested the SQL queries individually in DB Browser for SQLite using the farmersmarket.db database. I checked the returned results to make sure the SELECT queries produced the expected output and verified that the INSERT, DELETE, and UPDATE queries made the intended changes to the product_units table.

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

N/A

Checklist

• I can confirm that my changes are working as intended

[niyazmnazari]

Thank you for submitting Assignment 2. All queries are complete and correct. Section 1 is not submitted.
Mark: 20/70

[niyazmnazari]

Thank you for submitting the ERDs of section 1.
Mark: 70/70