Thank you for pointing that out Kaarel you saved me some time.
I wonder, Patric, if you ever read the source code of the OS you are
developing for or if you ever read the source of the compilers you use
because it is most likely that there are bugs and following your
argumentation: "a feature is there but you have to reimplement it every
time you write an app because you are resposible as developer for the
propper working of the app" you'd have to check all this. But you don't
because you expect these things to work as documentet. If I use a RDBMS
which supports foreign keys I expect the developers that they have red
the theory and standards about it and having them implemented. Because
adding a feature to an app and saying - if any problems occure - "was
just a trail you have to reimplement it" is imho absurd.