Is it possible to create a SQLite database on ESP32?

[S420L]

Hey--new user to micropython here.

I've used Ampy to load micropython and boot.py to my board (ESP32 devkitv1--I think this is basically a node MCU knockoff).

Importing SQLite3 like in normal Python didn't work, so I tried

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upip.install("micropython-sqlite3")

which was suggested by some sites, which didn't work.

Next I tried downloading the source code for SQLite3 and FFILIB from https://github.com/micropython/micropython-lib and putting these files directly on my board next to boot.py. At this point I got a NoneType error stemming from this line of code in SQLite3.py:

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sq3 = ffilib.open("libsqlite3")

I downloaded libsqlite3 from this site: https://cppget.org/libsqlite3 and running

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import sqlite3

in the REPL still resulted in a NoneType error.

Long story short--am I doing something wrong, or is it not even possible to run a SQLite database on the ESP32 yet?

[dhylands]

micropython-sqlite3 will only work on versions of micropython which have FFI. It's basically just a frontend for the C version of sqlite3, which is probably way too big to run on an ESP32.

I suppose it might be possible to port it to an ESP32. The libsqlite3.a file on my Mac is 1.8 Mb. But I'm going to guess it would take a substantial amount of effort since I imagine that sqlite3 makes extensive use of the C runtime library functions, many of which are unimplemented for micro platforms. You'd probably also need quite a bit of RAM.

[jimmo]

Some experiments were done a few years ago (~2014) which showed that a cut-down SQLite is about 200k of ROM, and apparantly wasn't that hard to implement.

I'm curious what sort of stuff you'd use SQLite for on a microcontroller though.

As Dave points out, micropython-lib is very confusing because half of the stuff there doesn't work on most ports. I'd like to fix this -- see https://github.com/micropython/micropython-lib/pull/376