If you need some book to get you started with SQL I would you recommend "Database System Concepts". I must warn you that there is a lot of theories in it. So if you are reading it, skip chapters that are not relevant for you.

Just start with mySQL. Easy to install and maintain. It's a very popular database also with other programming/script languages. The other databases you list are high-end products and often cost you money. You might also want to spend some time on data modeling and SQL in general.

FYI: Most of the "high-end" DBs come in free versions. SQL Server, Oracle, and DB2 (which wasn't on the original list, but is what we use - and what I use as the back-end to the CB stats page) all have free versions (not to be confused, of course, with open-source). I suspect that the official support is the same, too: none. But I've got a lot of help on forums, usenet, and IRC, so no complaints so far.

I would recommend NOT to start with MySQL. It often behaves very different from most other databases. (This is not an evil plan, just optimizations for special cases in some applications. And annoying in all other applications.) Good documentation.

Oracle is nice, if you have a good DB admin that manages it for you. Everything seems to be documented, even Larry Ellison's coffee mug. You just have to know where to search for the documentation. And Oracle brings TONS of software, including Apache, Perl, Java and every tool you can think of. Bloatware.

MS SQL is easy to set up (just click the "continue" buttons until they disappear ...), but it can be a real PITA when it comes to concurrent access, locking, multiple active statements, and access from non-Windows systems.

PostgreSQL is easy to set up, clean, well documented, and it has a very short gotchas list. (And for me, it feels like Oracle done right.)

SQLite is small, low-fat, and can easily be embedded. But it has a very unusual type system.

My recommendations:

• For fun projects as well as for new commercial projects, I would recommend to use PostgreSQL.
• If you want to learn more, learn Oracle, then MS SQL, followed by MySQL and SQLite. (Clean to dirty order.)
• If you have to deal with web hosting, you should learn MySQL (available nearly everywhere, but often in ancient versions) and SQLite (for hosters unwilling to provide a usable database), remembering that they have unusual behaviours.
• If you want to earn money, you should know all of them, including the "light" versions (SQL Express, Personal Oracle). You sould also try to learn DB2 and other RBDMS.

Alexander

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Today I will gladly share my knowledge and experience, for there are no sweeter words than "I told you so". ;-)

That being said, as has been said previously on this thread, MySQL would provide a better (aka far cheaper:-) starting point - from there you can, if funds permit, then go on to Oracle/Informix...

If you're just trying to learn the system, funds are not an issue with Oracle. They only want you to pay once you're hooked.

The reasoning for this strategy is very well explained in Information Rules.

If your reason for dismissing MS SQL is its poor ANSI SQL support, wouldn't it be more consistent of you to suggest something more SQL compliant amongst the free database servers, i.e. PostgreSQL or Firebird (even SQLite is better)? MySQL has been worse in supporting standard SQL than Microsoft (at least since MS SQL 6.5).

If you're completely new to databases, then you'll definitely benefit from having a go with SQLite.

It's extremely easy to install and use (you can be up and running inside a couple of minutes). Although it doesn't support all the fancy features of other databases, it covers everything you need to get going. Once you decide you want to play with the shiny features, it'll be pretty easy to migrate, and your knowledge won't be wasted (it's a really handy tool to know ;))

Beyond that, well, it depends what you want to do. PostgreSQL has evolved into an absolutely brilliant "enterprise-quality" database, and there's a wealth of documentation and an active community.

In my opinion, MySQL is kinda going downhill a little nowadays (its particular niche is being squeezed by SQLite and Postgres), and who knows what Oracle are going to do with it. That said, there's plenty of people out there using it.

I'm no expert on commercial databases, all I can really tell you is that Oracle can be rather complicated, but there's plenty of work out there for a good Oracle DBA.

If you do nothing else, dedicate an hour to playing with SQLite.

I'd go with mysql and sql-server express. They are both free, and using two different systems will mean that:

• You will be more aware of the sort of differences you will run into when using different db engines.
• You will learn to write easily portable code
• You will have more to put on your CV

map{$a=1-$_/10;map{$d=$a;$e=$b=$_/20-2;map{($d,$e)=(2*$d*$e+$a,$e**2
-$d**2+$b);$c=$d**2+$e**2>4?$d=8:_}1..50;print$c}0..59;print$/}0..20
[download]

If the goal is to learn and to improve your CV, I would install all these systems.

But definitely include Oracle: it's pretty much the gold standard of database systems, and there is always well-paid work. Oracle is to be avoided if you have to pay for the system (it's ridiculously overpriced) but for a developer it is a good skill to have. There is a free developer install.

If you also install the free/opensource systems PostgreSQL, MySQL and SQLite, you can learn how to write programs that talk to the different systems in the same way (=with the same/similar SQL statements). This way you'll learn the differences and specific strengths of each system.