The first customer of IBM Research's System R relational database was Pratt and Whitney in 1977. [1] IBM didn'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.
