Question of the Day - Persistence category

Horrible JDBC Code and What's Wrong With It

Wed, 12 Nov 2008 13:54:00 GMT

Ah, Efficiency: Thou art a goddess who deserves worship, adulation, sacrifice, but thou art also a goddess who gets said worship, adulation, and sacrifice in all the wrong ways. Here's some JDBC code validating a login, trying to be good code (I think!)... that gets it wrong in almost every way possible.

Are JDBC statements portable across databases?

Mon, 10 Nov 2008 12:07:00 GMT

Ah, JDBC. Sometimes, people want to write JDBC code, because SQL is friendly and safe; then they discover that they actually don't want to deploy on MySQL after all, and they run into problems. The question is usually formed in this way: "If I write my SQL in a prepared statement, is it going to work the same way in $OTHER_DATABASE?"

How can I automatically expire data from a database?

Sat, 30 Aug 2008 14:29:00 GMT

Another fairly common question: how can I expire data from a database? This is a case of applying lipstick to a pig: there are ways, to be sure, but the real problem is that you're using a database - a permanent datastore - to handle data that's short-lived.

My data structures have changed - how can I migrate my data model?

Thu, 28 Aug 2008 20:11:00 GMT

Sometimes, people design data structures, persisted entities, only to find that - gasp! - their data structures are more fluid than they expected. When all of your data is transient - meaning that it can be destroyed safely - that's no big deal, because you just drop the tables in question (or the whole database) and start over. (Sound familiar, Rails fans?) Sometimes, that's not enough - so what do you do?