[Mason] database qs

[Karl S. <ka...@dm...>]

I've only been toying with Mason for the last couple weeks.  I haven't
done web development in about a year.  At that time, my tool of choice
was ASP. I am finding it difficult going from
Server.CreateObject("ADODB.Connection")
to using DBI.  man DBI and man DBD::mysql are both extremely useful for
using DBI, but how best to utilize it through mason is a small mistery
to me.  I think my main problem is that with ASP, there was no such
thing as a persitent connection (as a matter of fact, you were supposed
to close the connection as soon as possible), and now I'm worried that
I'm not tweaking things right.

Most (if not all) of the information I have concerning using DBI with
Mason
comes from 1 question in the FAQ.    This leads me to believe one of
three
things:
  - Mason or mod perl are not the ideal solution for database driven
sites, or
  - My strong dependency on databases is unique, or finally;
  - People who write the mason documentation don't realize the dominance
of database driven sites.

Don't get me wrong, I can open a connection through mason to a database
and do eveyrthing I need with it.  But database connections, and
recordset fetching are by far the number one cause of latency on
high-traffic websites, and I want to know all the ways to do it; along
with the strength
and limitations of each.   I think *if* mason is capable of driving
heavy
database driven sites, far more documentation, examples, and discussion
need be made about it.

Right now, this is what I have.

In handler.pl (outside of "sub handler")

  {  package HTML::Mason::Commands;
     use vars qw($dbh);
     use Apache::DBI;
  }
  I believe that the above code makes the $dbi variable globally
accessibly, and that it imports the Apache::DBI package.


  next I have in sub handler:

   my $datasource = "DBI:mysql:database=blah;host=localhost";
   my $username = "blah";
   my $password = "blah";
   my $attr = { RaiseError=>1 ,AutoCommit=>0 };
 #  Apache::DBI->connect_on_init($datasource, $username, $password,
$attr);  #  Apache::DBI->setPingTimeOut($datasource, 0);
   $HTML::Mason::Commands::dbh = DBI->connect($datasource, $username,
$password, $attr);

  ok, so the first 4 lines are DBI related.  The next 3 lines are where
I start getting confused.  The 2 commented out lines come from the faq,
whereas the bottom line comes from the Admin Manual (on how to create
global
varibables).   AS you can see, I decided to follow the admin manual's
suggestion, since it makes sense to me.  Am I supposed to be using one
or the other? Or are they supposed to be used jointly?  If I have the
choice, what is the difference, and which do I want.  How does
Apache::DBI->connect_on_init($datasource, $username, $password, $attr);
assign a value to the $dbh global I made?

  With the code that I have now, i don't have any problems, because I
have a nice $dbh variable i every page which I can do anything "man DBI"
tells me. but what if I didn't have access to handler.pl ?  Would my
only alternative be to connect from each component to the database? ala:

  use Apache::DBI;
  my $dbh = DBI->connect(...);
  ...
  my $dbh->disconnect();


  Obviously this costs me a connection each time I hit that component.
This is how ASP does it with ADODB, there are no persistent connections
(unless ODBC / OLE DB are doing something in the background??) and I
never really saw it as being a huge problem.  Are database connections
more costly using DBI and that's why we want to make them persistent?
or is windows just sloppy and offers us no solution.

  What are the other ways to create database connections?  Both
persistent and not.

  I realize I could mix the two, and have

  {  package HTML::Mason::Commands;
     use vars qw($dbh);
     use Apache::DBI;
  }
  in my handler.pl

  and then $dbh->connect(...) in each necessary component - though I
don't see that saving me much overhead.

  Hope my concerns make sense.

  Thanks,
  Karl