Creating, Reading, Updating and Deleting (CRUD)

Almost everything an application does to data is one of four operations, known as CRUD:

Operation	SQL
Create	`INSERT INTO table (cols) VALUES (...)`
Read	`SELECT cols FROM table WHERE ...`
Update	`UPDATE table SET col = value WHERE ...`
Delete	`DELETE FROM table WHERE ...`

Always include a WHERE on UPDATE and DELETE unless you truly mean every row. Always pass values as ? parameters, never by pasting them into the text. Changes are held until you commit() them to make them permanent.

Examplepython

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Quick check

Which statement changes existing rows?

UPDATEINSERTSELECT

Your turn: write the code

Raise every price by 10 for products whose name is 'pen' and print the prices as a list ordered by id.

Finish the quick check (and any code exercise) to complete this lesson, or mark it done yourself.

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