I think a lot of smaller companies would struggle if that was still a requirement, but if relational/SQL had not come along we’d have something else like it.
Indeed SQL was not the only local maxima we could have gone for, but the point is that having an easy to use database with a powerful query language did not reduce the number of jobs, but instead increased it. Instead of a few companies hiring a lot of developers, we have a lot of companies hiring a few. The latter will usually mean more jobs.
Not really. There were a ton of ISVs competing with Oracle and pretty much every mainframe and minicomputer maker also had their own database products, many of them non-SQL.
All commercial databases pre-Oracle were non-SQL. Watching that history get rediscovered and pushed as an improvement by people mostly too young to know better — so-called NoSQL databases — brings to mind Alan Kay’s quip about the software industry constantly reinventing the flat tire.
The hash-based Pick OS/database came out before Oracle but only ran on a few computers from Microdata and later Pr1me and Honeywell. Pick-based systems remained popular into the early 2000s in some sectors. A friend of mine still works on one, for a state government agency.
You could construct a database management system from the ISAM-based libraries for COBOL or Fortran, but I wouldn’t call those database management systems comparable to Oracle. Mostly they didn’t have a query language per se — you had to write code to get anything in or out. And they ran as part of the application process, not as a separate server dedicated to running the database engine.