I am aware of the implications that hashing something more than once correctly will increase the security of a system, but doing it incorrectly will decrease it, as noted here and on various other sources.
But I stumbled upon a feature of Keepass, where the password database is encrypted N times to increase the work factor for brute force or dictionary attacks. This part explains how it is done: Protection against Dictionary Attacks
While I think that I am aware of the implication of hashing several times I am unsure whether encrypting several times, as explained above, increases robustness of the database.
Disclaimer: I've read Keepass Dictionary Attack Protection Strategy