Going way back, the easy answer for me is the Paradox desktop database from Borland. I used it in DOS in 1990; Windows kind of killed it. It was amazingly easy to build apps in it.<p><a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Paradox_%28database%29" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Paradox_%28database%29</a><p>Although reading that page I see that it still exists!? So maybe it doesn&#x27;t qualify for this question.<p>[Edit: I see the dBase&#x2F;FoxPro family mentioned down below. Same idea, roughly. Also great.]