Transactions, ACID and Integrity - Database Cheat Sheet

A transaction from BEGIN to COMMIT or ROLLBACK, then each ACID promise shown in SQLite: a two-step change that fails halfway and is rolled back, constraints refusing bad data with SQLite's own errors, and the four SQL languages.

On the sheet:

- One transaction, two ways to end: BEGIN, the steps, then COMMIT or ROLLBACK

- ACID: four promises, one line each

- Atomicity: a step fails halfway, and ROLLBACK

- Consistency: CHECK, FOREIGN KEY, UNIQUE and NOT NULL refusals

- The five guard rails: and the foreign key setting in SQLite

- COMMIT: a patient and a first visit saved as one unit

- Isolation and durability: what each promise means

- The four SQL languages: DDL, DML, DQL and DCL

- Data you can trust: accurate, available, protected, named well

Two A4 pages, printed front and back, sized to print once and keep beside you while you work. Written in short sentences and plain English, for readers whose first language is not English and clearer for everyone else because of it.

It pairs with the Design Principles, ACID & SQL book, so you can learn each idea in full and then revise it here in two pages.

Every query on this sheet was run against a live database before the page was printed, so the result you read is the result you get. Instant PDF download. By M.R. Sterling.