FastAPI Tutorial: Give some more background on Redis

[aeschli]

Testing #22302

I'm looking at the 'Replace the database' section. I'm new to Redis.

It explains nicely what line I need to replace with what, but I'm puzzled of what the new code means and how redis works.

redis_client.hincrby(f"item_id:{item_id}", "quantity", quantity)

what does this call do? What is hincrby. What's the effect to the database?

Maybe it is easier to start with the set:

redis_client.hset(
            f"item_id:{item_id}",
            mapping={
                "item_id": item_id,
                "item_name": item_name,
                "quantity": quantity,
            })

This seems to store an object with multiple properties. And hincrby allows to increment one of the properties?

[luabud]

Thank you so much for the feedback! I completely agree. I added a bit more of explanation around Redis and its methods throughout that section (microsoft/vscode-docs@5b8cdfc). I also added more explanation about the hashes we'd be using right in the beginning of the session, to try to make the whole edits clearer.