From: Jan Steinman Date: January 16 2012 4:35pm Subject: Re: delete all hosts using a wildcard List-Archive: http://lists.mysql.com/mysql/226608 Message-Id: <29587D3D-67CF-4E31-A81E-984BF047CDBB@Bytesmiths.com> MIME-Version: 1.0 (Apple Message framework v1084) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable > From: Tim Dunphy >=20 > ... this is just a test environment so getting rid of those users = won't have any meaningful impact... I think what Paul (who wrote a book on MySQL, by the way) was getting at = was that you risk what database folk call "referential integrity issues" = if you mess with *any* data without knowing where else it is used. But this has a bigger impact than if you mess up referential integrity = on your own tables. It could be that MySQL is making certain assumptions = -- such as a `user` record WILL be available if referenced in some other = privilege grant -- that will break things badly, making such tables (or = functions, or procs, etc.) unreachable. This could turn into a very = confusing "learning opportunity" where changing one thing has = far-reaching unintended impact. Or it may not, if you don't have other = privileges defined, in which case you may have "learned" the false = assurance that you can get away with such a thing. I've had the former "learning experience" -- that messing with privilege = tables directly resulted in strange behaviour that ended with me = trashing the entire thing and re-installing from scratch. My rule-of-thumb: if MySQL gives you a facility for manipulating = system-level tables, just use it! :-) ---------------- :::: Jan Steinman, EcoReality Co-op ::::