I'd strongly recommend not doing that. Jira's database is a data store, not a reporting model, and you certainly can't write to it.Could you explain what you are actually trying to achieve for the end user and why the custom fields can't already do it?
You would need an add-on for it. For example, Power Custom Fields Pro
You can create a combobox which would produce values from a database or JIRA API. I would strongly recommend not to query Jira database for information. Use Jira API instead.
Hey Atlassian Community! Today we are launching a bunch of customer stories about the amazing work teams, like Dropbox and Twilio, are doing with Jira. You can check out the stories here. The thi...
Connect with like-minded Atlassian users at free events near you!Find a group
Connect with like-minded Atlassian users at free events near you!
Unfortunately there are no AUG chapters near you at the moment.Start an AUG