For our course administration we use (already for several decades now) an application which was developed in-house, combined with a 45-table database on Db2 for z/OS.
The application originally consisted of just a 3270 front-end using the ISPF Dialog Manager and written in COBOL. In the course of the years, this application was extended with more panels (and the corresponding COBOL coding), written by different (former and current) colleagues, and internship students.
We did not necessarily want to get rid of COBOL, nor of the user-friendly 3270 interface panels. But we wanted the application to become more modular and layered, and we more specifically wanted to enable access to the database from other entry points, but sharing the same business logic.
At that point, ten years ago, we made the lucky decision to rewrite the most important business logic building blocks of the (then) COBOL software as modules, by converting them into Db2 stored procedures, written in SQL PL.
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