Database lib with indices on SD card

I'm making a project which should use large amount of data on ATmega2560. To storage and fast access, it have to be placed in database which support indices (index fields). It consists several tables with dozen of fields each and large ammount of records, in total file is at leas about 1GB

I have found only this, however, it seems it use tables only without indices"

Perhaps some other more suitable lib exists?

Ideally, something as SQLite (, but much rudimentar adapted for MCUs.

It's an unusual ask. If you have that much data to manage, a more conventional approach would be to put the data elsewhere (on a PC or Pi perhaps) and have the the Arduino get what it needs on demand. What are you trying to make?

This is some kind of GPS navigation project and I need to involve maps with Nokia 3310 B/W LCD. Similar as Garmin Edge B/W series.

It should save battery, working on 3xAA NiMH. Thus RPi is not suitable.

This is just a hobby project and I'm almost certain this all could fit in ATmega2560. All parts except maps already works fine.