I'm aware that an Ignition Edge client on its own cannot do SQL queries as per this page.
Is it possible for an Ignition Edge client to do an SQL query if it is connected to a central (fully licensed) Ignition server? The primary use for this central Ignition server would be to act as a Tag Historian.
No. Edge cannot do SQL queries. Full stop.
Edge Panel is $1,615.
One Vision seat for "full" Ignition is $1,918.
If you haven't bought anything yet, pay the extra.
Perhaps I'm overlooking something... I see no issues with a licensed Edge gateway sending a message to a licensed full gateway, full gateway receiving message & executing a database query, then returning results of query to the Edge gateway.
https://docs.inductiveautomation.com/display/DOC81/system.util.sendRequest
There are a few forum posts that expand on specific messages between gateways. Also, Edge Compute license may be required. Is it worth it? Without a specific use-case, that question can only be answered by the designer.
Ignition Edge Solution
Ignition Edge Core
$215Ignition Edge Compute$430Ignition Edge Panel$1,400
Number of Licensesx1
Subtotal$2,045 USD
It's literally cheaper to do it with full, unless of course you're using Perspective.
Thanks everyone for the input, much appreciated. Just assessing all options.
Ok. Sounds like a maintenance and UI development nightmare to me. Edge is still not doing SQL queries. {Before you mention it, including actual SQL in such a message is unsafe, insecure, and simply crazy.}
You'd basically have to design an API which while doable is not a small undertaking. The quick easy way would be sending raw SQL and yea that's a security nightmare.
100% agreed.
Q: Can Edge gateway query a database directly? A: No (not without exposing loopholes, not with a UI development and ongoing maintenance nightmare). No.
Q: Can Edge HMI act as a Tag Historian? A: Yes, to the limitation that Edge was designed for (~1 week of data). For majority of Edge cases, this should be perfectly acceptable.
Q: Can Edge HMI message a central gateway to retrieve long-term historical data? A: Technically, yes. Safely, securely, without a custom API? Absolutely. Should anyone consider this option? Probably not, not without a very good reason.
I think sending a message for the server to execute sql from the client is a good idea. Because security is resolved in the connection between server and client and if the database is in the same system than the server you can access safely to it.
As with any connection to a database permissions must be adjusted to avoid unnecesary exposure (ie don't access with root).