If you support packaged applications, you'll be having an Oracle backend. Oracle was very clever offering free development licenses to software developers year

If you support packaged applications, you'll be having an Oracle backend. Oracle was very clever offering free development licenses to software developers years ago. This made them the db of choice for people buying a premade solution. Nowadays it is different because we have a lot of open source DBs available to test for free; but long running monolythical apps won't change easily.