Can you use databases are even a tiny bit relational with App Inventor?

[ABG]

Logging Marathon Runner Checkpoints in Google Sheets

This sample is intended to show how to use Google Sheets aggregation functions like MAXIFS to summarize multirow log data into single line summaries. This sample uses the New York City Marathon as a base, though it probably can't scale to the 53,000 runners. It is based on three sheets: Checkpoints, a list of locations each runner must cross on his route Mileposts, a detail list of runner checkpoint timestamps Runners, a master list of runners, with identifying bar codes and stats Checkpoin…

The spreadsheet component gives you access to Google Sheets, where you can use =VLookup() functionality.

You can alternatively use AI2 lookup in pairs blocks or dictionary lookup in memory.