pugh!

The freeware OpenOffice Base
<http://www.openoffice.org/product/base.html> is modeled on, and very
similar to, Microsoft Access
<http://office.microsoft.com/en-us/access>. It comes with a default
database, HSQL <http://hsqldb.org/> just as Access comes with the
default Access database. However, OpenOffice Base can be used with any
database that has a JDBC driver just as Microsoft Access can be used
with any database that has an ODBC driver. In other words, OpenOffice
Base is not really a database although it includes one. You can use
OpenOffice Base as a database front end in a manner similar to TOAD
but it is oriented towards a user who wants to provide data entry and
reporting rather than database administration.

Actually, since Sun provide a JDBC to ODBC driver, OpenOffice Base can
be used with any database that has an ODBC driver and I use it to
connect to a Microsoft Access database.

Just to confuse you, there is an ODBC driver for Derby so you could
use Microsoft Access as a front end to a Derby database!  There are
some problems with the Derby (a.k.a. Cloudscape) ODBC driver that I
have documented at <http://www.profectus.com.au/ee_cloudscape.html>.

Actually, although I don't favor MySQL for technical reasons, it truly is
freeware if you use it in conformance with its GPL license.  The version
doesn't seem to influence that, only whether you link to their product for
commercial gain.

PostgreSQL, <http://www.postgresql.org/>, is robust, highly scalable, largely
SQL-conformant and has useful extensions.  It's especially suitable for those
who swim happily in the world of SQL, with all its views and subqueries and
what-not.  It uses the BSD open-source license which is much less restrictive
than GPL for those who wish to (ab)use PG for gain.
<http://www.postgresql.org/about/licence>

MySQL is the /de facto/ standard for web sites, particularly as the "M" in the
widely-adopted "LAMP" (Linux Apache MySQL PHP) architecture.  From what I've
read, that model has limits to its scalability.  Personally I prefer the more
"enterprisey" approach of heavily-architected strong systems, which favor the
use of Java and PostgreSQL, while still relying on the "L" and "A" components,
adding Tomcat, JSF - MyFaces or the Sun Reference Implementation (RI),
Glassfish or Geronimo or JBoss, maybe a dash of Spring, plus Hibernate or
Apache OpenJPA for the data-access layer.

The choice of architecture is a wholistic one - consider more than just the
database but how to tune all the components.  Hardware is relevant.  Does your
application justify, or rather, require RAID arrays with battery backed-up
(BBU) caching controllers?  Do you make a service guarantee?

That said, I'd still use Postgres over MySQL even for more lightweight use,
since it isn't really complex to manage except as your operational needs make
it so anyway.  Thus I favor a LAPJ architecture for web sites, prototypes,
more without bounds.

FWIW, I tried SQuirreL on the recommendations upthread - it works great with
Postgres.  I had to tell SQuirreL of the JDBC JAR, which I had previously
downloaded from <http://jdbc.postgresql.org/> to upgrade the default Linux
version.  That configuration took about five minutes, the very first five
minutes I had ever used SQuirreL, and it was painless and obvious.  Their
splash screen is pretty, too.

<http://squirrel-sql.sourceforge.net/>

No surprise in that. Support 8x5 or 24x7 always cost money.

You can buy a commercial product or find someone that are
willing to support Derby if that is a problem.

Neither SUN nor IBM want to provide free support.

It is open source.

It is free for anyone that can accept the GPL license
with FLOSS exception MySQL use.

The very short version is:

you do not distribute your code outside your own company => no
problem

your code is open source => no problem

else => you need to consult with lawyers whether you need to
buy a commercial license or not

If you buy then you get support as well. And that support
may be worth all the money if it is production.

GPL and all other open source does not really distinguish between
commercial and non-commercial. The distinctions goes between open
source and closed source and distributing to external entities or not.

Arne

Cloudscape is no longer actively supported by IBM [1]. IBM continue to
contribute to Apache Derby. Derby is supported by the Apache foundation
in the sense that they coordinate/provide further development and bug-fixes.

If you want to purchase an annual support contract for Derby, you can
buy that from Sun under the JavaDB name [2]

1: http://preview.tinyurl.com/2d64o6
2: http://developers.sun.com/javadb/support/

Oops! I certainly did not intend to say either of those things. The
reason the write up on Derby is longer than the rest is because I use
it and followed its evolution. I'm not sure why you concluded that
Derby has problems. If you can tell me I will try to clarify the note
on Derby. Meanwhile, I will remove some of the detail since that page
is not the right place for a history of Derby.