> This is a simple one but I couldn't find out the answer.
> What is the difference between PostgreSQL and MySql?
That's not simple at all. To me, the biggest difference that MySQL is a
faux open source project. If you plan to use your db with an application
that you write or have acquired from another vendor, and that application is
not covered by the GPL, then you will need to purchase a license to use it.
Considering MOST uses of databases are with non-GPL applications, this means
that MySQL is no longer a truly OSS.
I have contributed code to both JDBC drivers (Matthew's MySQL driver back
before it was acquired by MySQL, and the PG JDBC driver), and PG remains a
true OSS, so my help remains faithful and open and free. MySQL's work, on
the other hand, is a true ripoff because the code I wrote for them is now
being sold by PG with their copyright even they didn't write it or pay me to
write it.
Can you tell I'm bitter <smile>?
That said, I switched to PG several years ago when MySQL didn't support
transactions. They have tacked that on now, and I don't know how it
performs or how reliable it is. They had some odd characteristics before,
like the first timestamp field would be automatically updated by the engine
as if it was a "last update timestamp." I never could figure out why
anybody would make the db do this "for you" since it's really not that hard
to add such a timestamp and set it when you update it (i.e. set
last_update_time=now() or similar). MySQL was quite fast, but I haven't
seen any new benchmarks about how fast it is compared to PG in transaction
mode.
David