[Someone]

I guess it uses a mixed-radix number with radixes 10-10-10-10-12-31 or 10000-12-31 (or, maybe, 10000-13-32 to allow for zero months and days) if the config flag ALLOW_INVALID_DATES (http://dev.mysql.com/doc/refman/5.5/en/server-sql-mode.html#...) is set.

I still fail to see why anybody would want that or even the default 'if you cannot figure it out, use 0000-00-00' mode, though. That flag makes a broken system more broken, and if someone wants more flexibility in storing dates, he could always use char(8) or so.

In the context of this article: if you use your database as a dumb store and put all logic in your application, why would you let MySQL decide for you that, e.g., 2000-12-34 becomes 0000-00-00 and not, for instance, 2001-01-03?

[lmm]

>if you use your database as a dumb store and put all logic in your application, why would you let MySQL decide for you that, e.g., 2000-12-34 becomes 0000-00-00 and not, for instance, 2001-01-03?

I'm not letting MySQL decide for me intentionally. My application should be checking my dates; if I ever get as far as attempting to store 2000-12-34 in the database, it's because I made a mistake in my code.

So when live customer data discovers some untested path, what do you want to happen? In my experience in real applications, silently storing "corrupt" data (which I can fix by hand as soon as I discover the bug) is better than throwing an error back to the end user, and those are pretty much the only options.

[freshhawk]

> silently storing "corrupt" data (which I can fix by hand as soon as I discover the bug) is better than throwing an error back to the end user,

I think this statement might be a good test if you want to predict which camp they will fall into.

I frequently store enough data that fixing anything by hand is a large task and my experience with these types of errors is that this silently corrupted data (no need for quotes, that's what corrupted means) is sometimes corrupted in a lossy way, so you can't fix it by hand or in any other way.

Even if you can fix it by hand and it's not lossy I still find the fail fast philosophy is right most of the time, I want an error logged so I get notified and can fix it even if that means that an end user sees an error (there was one after all).

I might be biased having had the experience of exactly this type of mysql error destroying months of data that was the result of very expensive marketing because no one noticed until they tried to analyze it. Mysql was silent and our testing had missed it (if it had thrown an error our testing would have easily found it).