Paul DuBois <p...@snake.net> wrote on 10/14/2011 10:40:21 PM: > Paul DuBois <p...@snake.net> > 10/14/2011 10:41 PM > > To > > Bill Ward <b...@wards.net> > > cc > > ZhangJun <gb2...@gmail.com>, <dbi-users@perl.org> > > Subject > > Re: why DBD::mysql need database name for connecttion ? > > > On Oct 14, 2011, at 7:31 PM, Bill Ward wrote: > > > On Fri, Oct 14, 2011 at 5:26 PM, ZhangJun <gb2...@gmail.com> wrote: > > > >> > >> in the pod: > >> > >> #################### > >> Class Methods > >> connect > >> use DBI; > >> > >> $dsn = "DBI:mysql:$database"; > >> $dsn = "DBI:mysql:database=$database;host=$hostname"; > >> $dsn = > >> "DBI:mysql:database=$database;host=$hostname;port=$port"; > >> > >> $dbh = DBI->connect($dsn, $user, $password); > >> > >> A "database" must always be specified. > >> > >> ################### > >> > >> why database is needed ? > >> the mysqlclient can connect to server without this, and then select > >> database. > >> > >> > > You need to connect to a database before issuing any database commands. > > Not necessarily. SHOW DATABASES, for example, doesn't need any > database selected.
http://search.cpan.org/~capttofu/DBD-mysql-4.020/lib/DBD/mysql.pm#Server_Administration The docs do tell how to run commands without a database but its not as obvious as connecting without a database name. > > In the connect call, the database following the second colon > actually is optional. > The second colon, I believe, is not. So is the official CPAN documentation wrong then? It does explicitly say " A database must always be specified. " > So "DBI:mysql:" is legal. Or "DBI:mysql::hostname" if you want to > specify a hostname. > > > > The > > mysql client just makes that easier to do interactively. In Perl you could > > just create a different object for each database if you need to connect to > > more than one. Why is this a problem? > > > > -- > > Check out my LEGO blog at http://www.brickpile.com/ > > View my photos at http://flickr.com/photos/billward/ > > Follow me at http://twitter.com/williamward > > Please consider the environment before printing this email.
