Maintenance for the week of April 7:
• PC/Mac: NA and EU megaservers for patch maintenance – April 7, 4:00AM EDT (8:00 UTC) - 9:00AM EDT (13:00 UTC)
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• ESO Store for maintenance – April 10, 12:00PM EDT (16:00 UTC) - 3:00PM EDT (19:00 UTC)
I would like to build an addon that would need to access a remote SQL server to store and pull information. Is this possible with the ESO Addon system? If so, is there anywhere that shows how?
No, no interaction with anything outside of the ESO game itself is possible with addons and very certainly will never be.
What you can do is save data in the saved variables which gets written to disk once you exit the game. Then have some program pick that data up and do whatever you need to do with your sql server. It can even produce some answer which said program puts back into the savedVariables file so next time you start the game your addon has the processed data.
So in a kind of offline way, you can do it by passing data to/from saved Variables. They are only read on startup and written on shutdown of ESO though. (You can do it more often by using /reloadui if you really want but that's disruptive)
This may or may not be sufficient for what you want to do but it's basically the only way to interact with outside servers or services. Have a look how esohead's addon pulls information from the game and prepares it for uploading to their site as an example.