What’s on the Isolation Levels poster
A 4-row table: Level · Dirty read · Phantom.
An anomaly marked yes can still occur at that level.
- Read uncommitted — yes — yes
- Read committed — no — yes
- Repeatable read — no — yes*
- Serialisable — no — no
* PostgreSQL's repeatable read prevents phantoms; the SQL standard does not require it. Isolation names are not portable.
Questions about the Isolation Levels poster
- What’s on the Isolation Levels poster?
- A 4-row table: Level · Dirty read · Phantom. An anomaly marked yes can still occur at that level. Read uncommitted — yes — yes; Read committed — no — yes; Repeatable read — no — yes*; Serialisable — no — no. * PostgreSQL's repeatable read prevents phantoms; the SQL standard does not require it. Isolation names are not portable.
- Who is the Isolation Levels poster for?
- Isolation Levels belongs to the Computing section rather than to a school year, because computing is not something one grade owns. Anyone learning data can pin it up — a beginner, a student mid-course, or someone revising years later.
- When should you use the Isolation Levels poster?
- Read committed is the usual default. Know what it still allows before relying on it. A wall chart earns its place by being glanceable from where the work is happening, so Isolation Levels belongs on the wall where that computing work actually happens, within glancing distance, rather than filed away.
- What other posters go with Isolation Levels?
- ACID, The CAP Theorem and Choosing a Chart sit alongside Isolation Levels in the Computing section. Printed together they make a wall rather than a single sheet, which is how a reference set actually gets used.ACIDThe CAP TheoremChoosing a Chart
- Is the Isolation Levels poster free to download and print?
- Yes. Isolation Levels downloads as a free PDF with no account, no email and no watermark, like everything else in the Computing section. Print as many copies as you like for a home, a classroom, a library or a tutoring group; reselling the file is the only thing the licence rules out.Read the licence
- What size does the Isolation Levels poster print at?
- Isolation Levels is a vector PDF laid out for US Letter, and prints on A4 with Fit to page — the same file, no separate download. Because every mark on it is drawn rather than photographed, it stays sharp enlarged to A3, A2 or A1 at a copy shop. Colour carries emphasis only, so a greyscale print of Isolation Levels loses nothing.Printing guide
Related posters
Charts that sit alongside Isolation Levels on the same wall.
Browse every Computing poster, or start from the full catalogue.