A friend of mine was working on decommissioning Oracle at his company for the past year or two. The company bought some software that was using Oracle years ago. Turns out it was relying heavily on DB procedures and to ditch Oracle they had to move all this logic out of it first. They tried to do it couple of times before but failed. The software works so this work had low priority and would be scraped eventually to focus on more important things. On like a 3rd try they finally managed to do it and are now Oracle free.