What's really weird is the Stockholm syndrome of the Oracle users: They are proud of these limitations. I've heard all of these:
* Boolean: You don't really need it, just use 0/1 or Y/N (or J/N or O/N or whatever NLS equivalent of Y/N you want). You might have to implement a few different mappers for the same data type, so what?
* Strings: Semantically, a null string and an empty string are the same. You should be grateful the database works this way. All other DBs are wrong (you hear this a lot in Oracle land).
* Dates: Oh, just ignore the time if you don't want it. What do you mean, time zones? Add the correct offset in your software, you lazy XXX. BTW, we migrated to a server with another time zone, hope this doesn't impact you?
Now there are things that oracle is good at, mainly being trustworthy and scalable with your data, especially in clustered environments. But postgress is slowly but surely eating Oracle's niche here, and mysql has demonstrated customers will tolerate anything for lower costs. So their main value proposition today is that they are Enterprise Class, and all the big boys run Oracle so either join the club or get laughed at by the big boys.