
@blub @garius Many years ago there was a use case for picking DB2, Oracle, etc. There either were no free RDBMS systems or the ones that existed weren't yet advanced / stable enough. It's hard to see a good use case today.
1968 or 69, Cincom released TOTAL(*), a network database.
1979: Oracle 2.3 First commercially available SQL RDBMS
1981: IBM SQL/DS(*) released
1983: IBM DB2(*) gains SQL
1983: Oracle 3.1.3 rewritten in C & ported to UNIX
1993 MS SQL Server, a rebadged Sybase, released for NT
1994: Postgres95, first version of Postgres with SQL replacing POSTQUEL
1995 May the first version of mySQL released "For personal use" whatever that means.
1995 September PostgreSQL relicenced under a FOSS licence.
2000 SQLite 1.0 released.
2001 SQLite 2.0 had transactions
(*)=For IBM mainframes.
There were other database systems available for other mainframes.