view release on metacpan or  search on metacpan

mysql/lib/DBD/mysql.pm  view on Meta::CPAN

        or

    $dsn = "DBI:mysql:$database";
    $dsn = "DBI:mysql:database=$database;host=$hostname";
    $dsn = "DBI:mysql:database=$database;host=$hostname;port=$port";

    $dbh = DBI->connect($dsn, $user, $password);

A C<database> must always be specified.

=over 8

=item host

=item port

The hostname, if not specified or specified as '', will default to an
mysql or mSQL daemon running on the local machine on the default port
for the UNIX socket.

Should the mysql or mSQL daemon be running on a non-standard port number,
you may explicitly state the port number to connect to in the C<hostname>
argument, by concatenating the I<hostname> and I<port number> together
separated by a colon ( C<:> ) character or by using the  C<port> argument.
This doesn't work for mSQL 2: You have to create an alternative config
file and load it using the msql_configfile attribute, see below.


=item mysql_client_found_rows

Enables (TRUE value) or disables (FALSE value) the flag CLIENT_FOUND_ROWS
while connecting to the MySQL server. This has a somewhat funny effect:
Without mysql_client_found_rows, if you perform a query like

  UPDATE $table SET id = 1 WHERE id = 1

then the MySQL engine will always return 0, because no rows have changed.
With mysql_client_found_rows however, it will return the number of rows
that have an id 1, as some people are expecting. (At least for compatibility
to other engines.)

By default this flag is disabled. However, you can enable it by default,
when installing the Msql-Mysql-modules with

  perl Makefile.PL --config --mysql-use-client-found-rows
  make
  make install

=item mysql_compression

As of MySQL 3.22.3, a new feature is supported: If your DSN contains
the option "mysql_compression=1", then the communication between client
and server will be compressed.

=item mysql_connect_timeout

If your DSN contains the option "mysql_connect_timeout=##", the connect
request to the server will timeout if it has not been successful after
the given number of seconds.

=item mysql_read_default_file

=item mysql_read_default_group

These options can be used to read a config file like /etc/my.cnf or
~/.my.cnf. By default MySQL's C client library doesn't use any config
files unlike the client programs (mysql, mysqladmin, ...) that do, but
outside of the C client library. Thus you need to explicitly request
reading a config file, as in

    $dsn = "DBI:mysql:test;mysql_read_default_file=/home/joe/my.cnf";
    $dbh = DBI->connect($dsn, $user, $password)

The option mysql_read_default_group can be used to specify the default
group in the config file: Usually this is the I<client> group, but
see the following example:

    [perl]
    host=perlhost

    [client]
    host=localhost

If you read this config file, then you'll be typically connected to
I<localhost>. However, by using

    $dsn = "DBI:mysql:test;mysql_read_default_group=perl;"
        . "mysql_read_default_file=/home/joe/my.cnf";
    $dbh = DBI->connect($dsn, $user, $password);

you'll be connected to I<perlhost>. Note that if you specify a
default group and do not specify a file, then the default config
files will all be read.  See the (missing :-) documentation of
the C function mysql_options() for details.

=item mysql_socket

As of MySQL 3.21.15, it is possible to choose the Unix socket that is
used for connecting to the server. This is done, for example, with

    mysql_socket=/dev/mysql

Usually there's no need for this option, unless you are using another
location for the socket than that built into the client.


=back

=back


=head2 Private MetaData Methods

=over 4

=item B<ListDBs>

    my $drh = DBI->install_driver("mysql");
    @dbs = $drh->func("$hostname:$port", '_ListDBs');
    @dbs = $drh->func($hostname, $port, '_ListDBs');
    @dbs = $dbh->func('_ListDBs');

Returns a list of all databases managed by the mysql daemon or
mSQL daemon running on C<$hostname>, port C<$port>. This method
is rarely needed for databases running on C<localhost>: You should
use the portable method

    @dbs = DBI->data_sources("mysql");

        or

    @dbs = DBI->data_sources("mSQL");

whenever possible. It is a design problem of this method, that there's
no way of supplying a host name or port number to C<data_sources>, that's
the only reason why we still support C<ListDBs>. :-(


=item B<ListTables>

*WARNING*: This method is obsolete due to DBI's $dbh->table_info().

    @tables = $dbh->func('_ListTables');

Once connected to the desired database on the desired mysql or mSQL
mSQL daemon with the C<DBI->connect()> method, we may extract a list
of the tables that have been created within that database.