On older versions of Ignition on the Config > Database > Drivers & Settings there used to be a column called JAR File(s) which seems to be missing on newer installs of Ignition.
The column was removed because it was essentially a lie; it wasn't guaranteed to be accurate to any actual filename on disk. The names of the files on disk are immaterial, in any case; for JDBC drivers we just load up every .jar file in a folder into a special database classloader, then ask that classloader for the provided class name for your driver.
Interesting. So does this mean we can drop a newer version of a .jar in this folder* C:\Program Files\Inductive Automation\Ignition\user-lib\jdbc and then restart the gateway without having to go in and edit the .jar file from the gateway config page?
*Note: I assume we'd have to remove / backup the old one from this folder first... not sure how it would handle multiple versions of the same Classname
Exactly that, yes.
And, indeed - be sure you don't have multiple jar files providing the same class. Basically what will happen is that one is picked effectively at random, which becomes an absolute nightmare to debug.
One final supplementary statement here regarding the filename (which is still tracked in the internal config DB, just not displayed on the drivers page anymore)--its only use was to make an attempt to delete that .jar file when replacing a given JDBC driver entry through the web UI (with the goal of avoiding the situation Paul just described).