The first customer of IBM Research&#x27;s System R relational database was Pratt and Whitney in 1977. [1] IBM didn&#x27;t release a commercial relational database until 1981. [2] The article is from 1978. Anyway MUMPS is probably simpler since than an SQL database since its database is a key value store. The big problem is that it made it easy to write unreadable code and people wrote enough of it to give it a bad reputation.<p>[1]:  <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;IBM_System_R" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;IBM_System_R</a><p>[2]: <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;IBM_DB2" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;IBM_DB2</a>