Read information from DB

[Maro Hamamjyan]

Hello,
We have a system, based on SQL DB, where we have all the necessary data about our users. I need to get all the users whose manager is the Reporter (the person who created the ticket). I have the managers list, I have the users filtered by manager, or can get them in SQL, but I need you to advice me to reach my goal (without using plugins). How to start? Should I just create an exe, which will read information from DB and put it under schedule, or I can install any soft, that will let me to connect Jira with DB?
Also in case i get the users I need how should I show the users in Jira Service desk? Should I use any API, that will allow to update the particular filed in particular thicket? Please let me know about the right direction to move on!
Thanks in advance

[Nic Brough -Adaptavist-]

I'm afraid "without using plugins" almost rules out what you're trying to do.

You need to find or write some code that can grab information from your database and display it in Jira.  This is going to need a plugin, unless you write something from the outside which pokes data into Jira over the REST API. 

I would strongly recommend an app though.  A REST call can only update fields and Jira data, so you would need to work from custom fields you can add, and it would lag, as you'd be responding to events or polling to see if or when updates were needed.  An app could read the database (or a copy) as needed and do the display in more in-line ways.