SQLToy

103 pointsposted 10 months ago
by akkartik

19 Comments

tekknolagi

10 months ago

Yesterday I found this and ported it to Python: https://github.com/tekknolagi/db.py

It's ~150LOC but doesn't have aggregates (yet)

emmelaich

10 months ago

Did you use the same data? I couldn't find it in the original.

tekknolagi

10 months ago

What do you mean same data?

emmelaich

10 months ago

I mean the data / tables used. The tables used in the original.

tekknolagi

10 months ago

I made up some stuff for tests and copied some tables from their demos

wood_spirit

10 months ago

It’s like a ray tracer: every programmer should write a toy sql engine!

A very long time ago I started writing a game in a weekend a for Ludum dare competition and ended up writing a toy sql engine of my own https://williame.github.io/post/59997353762.html

I still get the urge to make a proper one one day. With the sql features that I wish sql engines had. Hmmm. Need-sniping myself now… :)

barbegal

10 months ago

Great toy but it's a bit misleading not to touch on the query planner. All real SQL implementations will plan how to most efficiently run a query so the order of operations can be wildly different to expected based on the data and indexes available. This kind of tutorial makes it look like joins are very inefficient whereas a real database may make them highly efficient for a given query.

curtisblaine

10 months ago

I hoped this had a toy implementation of sql indices, but it looks like that's not the case: it just sorts the whole table on the fly on an ORDER BY.

aboodman

10 months ago

I mean that basically in an implementation of indexes. Move the on-the-fly sorts to behind a command, then change the insert/delete code to maintain them, and voila - indexes.

curtisblaine

10 months ago

Aren't indexes a static, pre-calculated way to avoid in-memory sorting on the fly?

jrop

10 months ago

I love projects like this that shed light on and demystify and otherwise mysterious process. Thanks for sharing!

dcreater

10 months ago

Would be great if it was literally any other language other than js

RodgerTheGreat

10 months ago

It would be very easy to follow along with a transliteration into any dynamic language language with halfway decent support for functional programming.

mhio

10 months ago

Why is that? There doesn't seem to be anything particularly esoteric in the implementation.