Isn't container-managed transactions the point of EJBs anyway? So database
transaction
facilities are no longer mission critical? Or am I missing something...
MySQL also contains some pretty practical advice regarding the
indiscriminate use of foriegn keys
(it even says they're only useful for visual design tools so designers can
more easily generate excess complexity
or something to that effect)
> -----Original Message-----
> From: Elias Martensson [SMTP:[EMAIL PROTECTED]]
> Sent: Tuesday, January 04, 2000 7:13 PM
> To: Orion-Interest
> Cc: Orion-Interest
> Subject: Re: EJB w/ different DB's
>
> On Tue, 4 Jan 2000, Brien Voorhees wrote:
>
> > From: "Frank Apap" <[EMAIL PROTECTED]>
> > > I am currently using hSql for my db with my ejb operations, but I want
> to
> > > switch over to a more reliable and documented db. Does anyone have
> any
> > > recommendations for simply but reliable database that will be easy to
> > switch
> > > to?
> >
> > I don't know if it integrates specifically with EJB but you might want
> to
> > check out MySql. It runs on lots of different platforms and is one of
> the
> > most popular free databases in use. I've been using it for development
> > recently and found it to be extremely fast, easy to setup, and fairly
> rich
> > in features. I'm not sure but I think it's Open Source, as well. You
> can
> > check it out at www.mysql.com. O'Reilly has a book that covers MySQL
> called
> > "MySQL & mSQL". It's available at BookPool, which has really good
> prices on
> > technical books http://www.bookpool.com/.x/nt696p9rmi/sm/1565924347 .
>
> I would definately recommend against MySql, it is missing several
> important features of which the most important one in transactions (in
> fact, I find it unbeliavble how a database that is missing such an
> important feature can be so popular).
>
> Missing transactions cause a lot of problems, but one of the grat ones is
> that it is impossible to take a backup of the database and be sure that
> you are able to restore it in a consitent state (I can discuss the
> numerous race conditions that can occur off this list if anyone is
> interested). Also, if the client crashes during a transaction you only
> know one this: That the database might be in an inconsistent state.
>
> There are other features that MySql lacks that at least I find to be
> equally important:
>
> o Views
> o Stored procedures
> o Subqueries
> o Row level locking
>
> The last one deserves a bit of exmplanation. It has to do with the fact
> that since it doesnt have transactions, it has to solve concurrecy issues
> in a different way. The solution takes by mysql is to create a command
> called "lock tables" that can lock one or more tables for exclusive
> access. While tables are locked no otherthread can access that table at
> the same time. The problem is that the whole table is locked. So if you
> have a large table of say 100K rows it means that each and every one of
> those 100K rows are locked when you do somehting to the table. Needless to
> say, that is very bad for performance.
>
> Another really annoying misfeature of mysql is that you cannot create
> indexes on VARCHAR columns. I assume you can figure out for yourself what
> this does to either performance or storage space required.
>
> Yes, you have propably guessed it. I have been burned by mysql. It took
> several weeks of screaming until I decided to ditch it. I'm very happy
> that I did and I'm writing this rant in order to prevent others from
> falling into the same trap.
>
> What should you use instead then? Well, I'd suggest any one of the Four
> Great ones: Oracle, Sybase, Informix or DB/2. From what I have been told
> DB/2 offers the best performance of any SQL RDBMS out there. At least
> that's the one with the best TPC score (at least on Solaris). The only
> ones out of the above 4 I have tested is Oracle and Sybase. My personal
> favourtite is Sybase, but that's just because that's the one I know best.
>
> Sybase 11.0 is free for all use (including commercial), the latest
> version, 11.9, is free for non-commercial use. The other 3 are also free
> for non-commercial use but I haven't checked their licenses in any detail
> so I guess you'll have to verify for yourselves.
>
> If for some reason you feel that you need a SQL RDBMS with source code (I
> can't understand why because the 4 I mentioned above are magnitudes better
> than the open sourced ones) then you can use PostgreSQL. I can't vouch for
> its performance but at least it has most features one needs, including
> transactions.
>
> And a final word, is mysql totally useless? In my opinion, yes. In others,
> no. The good arguments for the use of mysql that I have heard have been
> situations where all you do with the tables are individual select's and
> insert's. I would not classify EJB usage as siple inserts and selects.
> Especially once you want to use the transaction features of the EJB's.
>
> /E.
>
>
