Gads, someone else asking for E/R diagram support. We have 36 votes for this in Issuezilla. What is it with you guys?
First of all, MySQL Workbench really owns this space. Yes, I know, right now it only runs on Windows, but the next release will fix that. And, yes, I know it only works for MySQL, but the promise is that they will fix that too, albeit not right away.
Secondly, NetBeans DB tooling has a huge opportunity because we're part of the IDE. An E/R diagram tool doesn't really leverage that advantage. There are things we can do that will make your day-to-day experience of slogging code for database applications really nice. But we can't be doing that if we're spending all our time writing an E/R tool.
That said, we're looking very seriously at a simple read-only E/R plugin. First and foremost what people want is a way to understand the structure of their database and to communicate this to others. Being able to build a database design through visual tools is useful, but has a secondary order of demand.
Anyway, keep your eyes peeled to this space, all you E/R lovers.