A few days ago I read a question on the PostgreSQL mailinglists where someone asked if there is an Arduino library to connect to PostgreSQL. He had a network of hundreds of sensors worldwide, measuring weather data and sending it back to a central database.
The short answer was "No, use HTTP" The poster was not happy with this answer and explained that his MySQL solution works just fine, and MySQL is super for supporting it and it was a real shame that the PostgreSQL community flat out refused to create this.
The community replied with a couple of arguments:
- An arduino has limited memory. A library that can speak native PostgreSQL uses up quite a lot of that memory, while the application itself does not require any of it's functionality.
- Is it wise to have a $20 piece of hardware, located somewhere in the world, be able to login directly into a database?
-What happens when the master database is forced to upgrade and the protocol changes, how can you upgrade all the Arduino's remotely, simultaneously, and with an option to revert if there is a problem?
- Connecting to the database directly requires that the database's port is open in all routers etc between the node and the server, and the first thing any sysadmin will do is close all ports he doesn't think necessary, very much including 3306 and 5432.
Using HTTP solves all these problems, by using ony a handfull of bytes to send the data, using port 80, and connecting to a regular webserver that hides the database behind a protocol that has no need to ever change.
The moral of the story is that if you ask people a question, you may not get the answer you want, but you may get an answer you need. The key is to realise that your knowledge does have limits, as does your experience. You *will* encounter people who have thought things through, or who have more experience than you. It is up to you to investigate the claims and use the knowledge to your advantage.