# Designing a MySQL Table from a CSV

Design the destination table from the meaning of the data, not merely its appearance in a spreadsheet.

| CSV field | MySQL type | Rule |
| --- | --- | --- |
| match_id | VARCHAR(20) | unique and required |
| team_name | VARCHAR(100) | required |
| wins | INT | zero or greater |
| losses | INT | zero or greater |

~~~sql
CREATE TABLE team_results (
  result_id INT AUTO_INCREMENT PRIMARY KEY,
  match_id VARCHAR(20) NOT NULL UNIQUE,
  team_name VARCHAR(100) NOT NULL,
  wins INT NOT NULL,
  losses INT NOT NULL
);
~~~

A surrogate primary key supports database operations; the unique source identifier prevents accidental duplicates.

## Design questions

- Does one CSV row represent one entity or a relationship?
- Which values repeat independently and belong in related tables?
- Which constraints protect data quality?
- Will repeated imports insert, reject or update existing records?

Document and justify the chosen policy.

## Check

- [ ] Types and lengths fit expected values.
- [ ] Required fields are constrained.
- [ ] Duplicate behaviour is defined.
- [ ] Relationships reflect the solution’s data needs.