Using SQLite for exact search
I've been experimenting with SQLite a software library that provides a relational database management system, it is self-contained, serverless, and requires little or no admin.
SQLite is a C-language library that implements a small, fast, self-contained, high-reliability, full-featured, SQL database engine. SQLite is the most used database engine in the world. SQLite is built into all mobile phones and most computers and comes bundled inside countless other applications that people use every day.
In particular I've been looking at using it for very fast exact lookup of chemical structures. This tutorial https://www.macinchem.org/reviews/exactsearch/exactsearch.php takes you through setting up the database, storing chemical structures as SMILES strings and then accessing it using a Jupyter Notebook.
The second tutorial https://www.macinchem.org/reviews/exactsearch/usingexactsearch.php shows how to create a python script to access from the command line, and using AppleScript to access it from ChemDraw. This allows you to get the structure for a specific identifier or check for the identifier for a drawn structure.