DBD::mysql(3pm)

NAME

DBD::mysql - MySQL driver for the Perl5 Database Interface (DBI)

SYNOPSIS

use DBI;

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

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


$drh = DBI->install_driver("mysql");
@databases = DBI->data_sources("mysql");
   or
@databases = DBI->data_sources("mysql",
  {"host" => $host, "port" => $port, "user" => $user, password => $pass});

$sth = $dbh->prepare("SELECT * FROM foo WHERE bla");
   or
$sth = $dbh->prepare("LISTFIELDS $table");
   or
$sth = $dbh->prepare("LISTINDEX $table $index");
$sth->execute;
$numRows = $sth->rows;
$numFields = $sth->{'NUM_OF_FIELDS'};
$sth->finish;

$rc = $drh->func('createdb', $database, $host, $user, $password, 'admin');
$rc = $drh->func('dropdb', $database, $host, $user, $password, 'admin');
$rc = $drh->func('shutdown', $host, $user, $password, 'admin');
$rc = $drh->func('reload', $host, $user, $password, 'admin');

$rc = $dbh->func('createdb', $database, 'admin');
$rc = $dbh->func('dropdb', $database, 'admin');
$rc = $dbh->func('shutdown', 'admin');
$rc = $dbh->func('reload', 'admin');

EXAMPLE

#!/usr/bin/perl

use strict;
use DBI();

# Connect to the database.
my $dbh = DBI->connect("DBI:mysql:database=test;host=localhost",

"joe", "joe's password",
{'RaiseError' => 1});

# Drop table 'foo'. This may fail, if 'foo' doesn't exist.
# Thus we put an eval around it.
eval { $dbh->do("DROP TABLE foo") };
print "Dropping foo failed: $@\n" if $@;

# Create a new table 'foo'. This must not fail, thus we don't
# catch errors.
$dbh->do("CREATE TABLE foo (id INTEGER, name VARCHAR(20))");

# INSERT some data into 'foo'. We are using $dbh->quote() for
# quoting the name.
$dbh->do("INSERT INTO foo VALUES (1, " . $dbh->quote("Tim") . ")");

# Same thing, but using placeholders
$dbh->do("INSERT INTO foo VALUES (?, ?)", undef, 2, "Jochen");

# Now retrieve data from the table.
my $sth = $dbh->prepare("SELECT * FROM foo");
$sth->execute();
while (my $ref = $sth->fetchrow_hashref()) {

print "Found a row: id = $ref->{'id'}, name = $ref->{'name'}\n";

}
$sth->finish();

# Disconnect from the database.
$dbh->disconnect();

DESCRIPTION

DBD::mysql is the Perl5 Database Interface driver for the MySQL database. In other words: DBD::mysql is an interface between the Perl
programming language and the MySQL programming API that comes with the MySQL relational database management system. Most functions provided by this programming API are supported. Some rarely used functions are
missing, mainly because noone ever requested them. :-)

In what follows we first discuss the use of DBD::mysql, because this is what you will need the most. For installation, see the sections on
INSTALLATION, and "WIN32 INSTALLATION" below. See EXAMPLE for a simple example above.

From perl you activate the interface with the statement

use DBI;

After that you can connect to multiple MySQL database servers and send multiple queries to any of them via a simple object oriented interface. Two types of objects are available: database handles and statement
handles. Perl returns a database handle to the connect method like so:

$dbh = DBI->connect("DBI:mysql:database=$db;host=$host",

$user, $password, {RaiseError => 1});

Once you have connected to a database, you can can execute SQL
statements with:

my $query = sprintf("INSERT INTO foo VALUES (%d, %s)",

$number, $dbh->quote("name"));

$dbh->do($query);

See DBI(3) for details on the quote and do methods. An alternative approach is

$dbh->do("INSERT INTO foo VALUES (?, ?)", undef,

$number, $name);

in which case the quote method is executed automatically. See also the bind_param method in DBI(3). See "DATABASE HANDLES" below for more details on database handles.

If you want to retrieve results, you need to create a so-called
statement handle with:

$sth = $dbh->prepare("SELECT * FROM $table");
$sth->execute();

This statement handle can be used for multiple things. First of all you can retreive a row of data:

my $row = $sth->fetchrow_hashref();

If your table has columns ID and NAME, then $row will be hash ref with keys ID and NAME. See "STATEMENT HANDLES" below for more details on
statement handles.

But now for a more formal approach:

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.

host
port

The hostname, if not specified or specified as '' or
'localhost', will default to a MySQL server running on the
local machine using the default for the UNIX socket. To connect to a MySQL server on the local machine via TCP, you must
specify the loopback IP address (127.0.0.1) as the host.

Should the MySQL server be running on a non-standard port
number, you may explicitly state the port number to connect to in the "hostname" argument, by concatenating the hostname and port number together separated by a colon ( ":" ) character or by using the "port" argument.

To connect to a MySQL server on localhost using TCP/IP, you
must specify the hostname as 127.0.0.1 (with the optional
port).

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.)

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.

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_init_command

If your DSN contains the option "mysql_init_command_timeout=##", then this SQL statement is executed when connecting to the MySQL server. It is automatically re-executed if reconnection occurs.

mysql_read_default_file
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 client group, but see the following example:

[client]
host=localhost

[perl]
host=perlhost

(Note the order of the entries! The example won't work, if you reverse the [client] and [perl] sections!)

If you read this config file, then you'll be typically
connected to 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 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 documentation of the C function mysql_options() for details.

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.

mysql_ssl

A true value turns on the CLIENT_SSL flag when connecting to
the MySQL database:

mysql_ssl=1

This means that your communication with the server will be
encrypted.

If you turn mysql_ssl on, you might also wish to use the
following flags:

mysql_ssl_client_key
mysql_ssl_client_cert
mysql_ssl_ca_file
mysql_ssl_ca_path
mysql_ssl_cipher

These are used to specify the respective parameters of a call
to mysql_ssl_set, if mysql_ssl is turned on.

mysql_local_infile

As of MySQL 3.23.49, the LOCAL capability for LOAD DATA may be disabled in the MySQL client library by default. If your DSN
contains the option "mysql_local_infile=1", LOAD DATA LOCAL
will be enabled. (However, this option is *ineffective* if the server has also been configured to disallow LOCAL.)

mysql_multi_statements

As of MySQL 4.1, support for multiple statements separated by a semicolon (;) may be enabled by using this option. Enabling
this option may cause problems if server-side prepared
statements are also enabled.

Prepared statement support (server side prepare)

As of 3.0002_1, server side prepare statements were on by
default (if your server was >= 4.1.3). As of 3.0009, they were off by default again due to issues with the prepared statement API (all other mysql connectors are set this way until C API
issues are resolved). The requirement to use prepared
statements still remains that you have a server >= 4.1.3

To use server side prepared statements, all you need to do is
set the variable mysql_server_prepare in the connect:

$dbh = DBI->connect(

"DBI:mysql:database=test;host=localhost;mysql_server_prepare=1", "",
"",
{ RaiseError => 1, AutoCommit => 1 }
);

* Note: delimiter for this param is ';'

There are many benefits to using server side prepare
statements, mostly if you are performing many inserts because
of that fact that a single statement is prepared to accept
multiple insert values.

To make sure that the 'make test' step tests whether server
prepare works, you just need to export the env variable
MYSQL_SERVER_PREPARE:

export MYSQL_SERVER_PREPARE=1

mysql_embedded_options

The option <mysql_embedded_options> can be used to pass
'command-line' options to embedded server.

Example:

use DBI;
$testdsn="DBI:mysqlEmb:database=test;mysql_embedded_options=--help,--verbose";
$dbh = DBI->connect($testdsn,"a","b");

This would cause the command line help to the embedded MySQL
server library to be printed.

mysql_embedded_groups

The option <mysql_embedded_groups> can be used to specify the
groups in the config file(my.cnf) which will be used to get options for embedded server. If not specified [server] and
[embedded] groups will be used.

Example:

$testdsn="DBI:mysqlEmb:database=test;mysql_embedded_groups=embedded_server,common";

Private MetaData Methods

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 server running on $hostname, port $port. This is a legacy method. Instead, you
should use the portable method

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

Server Administration

admin

$rc = $drh->func("createdb", $dbname, [host, user, password,], 'admin');
$rc = $drh->func("dropdb", $dbname, [host, user, password,], 'admin');
$rc = $drh->func("shutdown", [host, user, password,], 'admin');
$rc = $drh->func("reload", [host, user, password,], 'admin');

or

$rc = $dbh->func("createdb", $dbname, 'admin');
$rc = $dbh->func("dropdb", $dbname, 'admin');
$rc = $dbh->func("shutdown", 'admin');
$rc = $dbh->func("reload", 'admin');

For server administration you need a server connection. For
obtaining this connection you have two options: Either use a driver handle (drh) and supply the appropriate arguments (host, defaults
localhost, user, defaults to '' and password, defaults to ''). A
driver handle can be obtained with

$drh = DBI->install_driver('mysql');

Otherwise reuse the existing connection of a database handle (dbh).

There's only one function available for administrative purposes,
comparable to the m(y)sqladmin programs. The command being execute depends on the first argument:

createdb

Creates the database $dbname. Equivalent to "m(y)sqladmin
create $dbname".

dropdb

Drops the database $dbname. Equivalent to "m(y)sqladmin drop
$dbname".

It should be noted that database deletion is not prompted for in any way. Nor is it undo-able from DBI.

Once you issue the dropDB() method, the database will be gone!

These method should be used at your own risk.

shutdown

Silently shuts down the database engine. (Without prompting!)
Equivalent to "m(y)sqladmin shutdown".

reload

Reloads the servers configuration files and/or tables. This can be particularly important if you modify access privileges or
create new users.

DATABASE HANDLES

The DBD::mysql driver supports the following attributes of database
handles (read only):

$errno = $dbh->{'mysql_errno'};
$error = $dbh->{'mysql_error'};
$info = $dbh->{'mysql_hostinfo'};
$info = $dbh->{'mysql_info'};
$insertid = $dbh->{'mysql_insertid'};
$info = $dbh->{'mysql_protoinfo'};
$info = $dbh->{'mysql_serverinfo'};
$info = $dbh->{'mysql_stat'};
$threadId = $dbh->{'mysql_thread_id'};

These correspond to mysql_errno(), mysql_error(), mysql_get_host_info(), mysql_info(), mysql_insert_id(), mysql_get_proto_info(), mysql_get_server_info(), mysql_stat() and mysql_thread_id(), respectively.

$info_hashref = $dhb->{mysql_dbd_stats}

DBD::mysql keeps track of some statistics in the mysql_dbd_stats
attribute. The following stats are being maintained:

auto_reconnects_ok

The number of times that DBD::mysql successfully reconnected to the mysql server.

auto_reconnects_failed

The number of times that DBD::mysql tried to reconnect to mysql but failed.

The DBD::mysql driver also supports the following attribute(s) of
database handles (read/write):

$bool_value = $dbh->{mysql_auto_reconnect};
$dbh->{mysql_auto_reconnect} = $AutoReconnect ? 1 : 0;

mysql_auto_reconnect

This attribute determines whether DBD::mysql will automatically
reconnect to mysql if the connection be lost. This feature defaults to off; however, if either the GATEWAY_INTERFACE or MOD_PERL
envionment variable is set, DBD::mysql will turn
mysql_auto_reconnect on. Setting mysql_auto_reconnect to on is not advised if 'lock tables' is used because if DBD::mysql reconnect to mysql all table locks will be lost. This attribute is ignored when AutoCommit is turned off, and when AutoCommit is turned off,
DBD::mysql will not automatically reconnect to the server.

mysql_use_result

This attribute forces the driver to use mysql_use_result rather
than mysql_store_result. The former is faster and less memory
consuming, but tends to block other processes. (That's why
mysql_store_result is the default.)

It is possible to set default value of the "mysql_use_result"
attribute for $dbh using several ways:

- through DSN

$dbh= DBI->connect("DBI:mysql:test;mysql_use_result=1", "root", "");

- after creation of database handle

$dbh->{'mysql_use_result'}=0; #disable
$dbh->{'mysql_use_result'}=1; #enable

It is possible to set/unset the "mysql_use_result" attribute after creation of statement handle. See below.

mysql_enable_utf8

This attribute determines whether DBD::mysql should assume strings stored in the database are utf8. This feature defaults to off.

When set, a data retrieved from a textual column type (char,
varchar, etc) will have the UTF-8 flag turned on if necessary.
This enables character semantics on that string. You will also
need to ensure that your database / table / column is configured to use UTF8. See Chapter 10 of the mysql manual for details.

Additionally, turning on this flag tells MySQL that incoming data
should be treated as UTF-8. This will only take effect if used as part of the call to connect(). If you turn the flag on after connecting, you will need to issue the command "SET NAMES utf8" to get the same effect.

This option is experimental and may change in future versions.

mysql_bind_type_guessing

This attribute causes the driver (emulated prepare statements) to
attempt to guess if a value being bound is a numeric value, and if so, doesn't quote the value. This was created by Dragonchild and
is one way to deal with the performance issue of using quotes in a statement that is inserting or updating a large numeric value. This was previously called "unsafe_bind_type_guessing" because it is
experimental. I have successfully run the full test suite with this option turned on, the name can now be simply
"mysql_bind_type_guessing".

CAVEAT: Even though you can insert an integer value into a
character column, if this column is indexed, if you query that
column with the integer value not being quoted, it will not use the index:

MariaDB [test]> explain select * from test where value0 = '3' \G
*************************** 1. row ***************************

id: 1

select_type: SIMPLE

table: test

type: ref possible_keys: value0

key: value0

key_len: 13

ref: const

rows: 1

Extra: Using index condition 1 row in set (0.00 sec)

MariaDB [test]> explain select * from test where value0 = 3

-> \G *************************** 1. row

***************************

id: 1

select_type: SIMPLE

table: test

type: ALL possible_keys: value0

key: NULL

key_len: NULL

ref: NULL

rows: 6

Extra: Using where 1 row in set (0.00 sec)

See bug: https://rt.cpan.org/Ticket/Display.html?id=43822

mysql_bind_comment_placeholders

This attribute causes the driver (emulated prepare statements) will cause any placeholders in comments to be bound. This is not correct prepared statement behavior, but some developers have come to
depend on this behavior, so I have made it available in 4.015

See bug: https://rt.cpan.org/Ticket/Display.html?id=

"mysql_bind_type_guessing" can be turned on via

- through DSN

my $dbh= DBI->connect('DBI:mysql:test', 'username', 'pass',
{ mysql_bind_type_guessing => 1})

- OR after handle creation

$dbh->{mysql_bind_type_guessing} = 1;

mysql_no_autocommit_cmd

This attribute causes the driver to not issue 'set autocommit'
either through explicit or using mysql_autocommit(). This is particularly useful in the case of using MySQL Proxy.

See the bug report:

https://rt.cpan.org/Public/Bug/Display.html?id=46308

As well as:

http://bugs.mysql.com/bug.php?id=32464

"mysql_no_autocommit_cmd" can be turned on via

- through DSN

my $dbh= DBI->connect('DBI:mysql:test', 'username', 'pass',
{ mysql_no_autocommit_cmd => 1})

- OR after handle creation

$dbh->{mysql_no_autocommit_cmd} = 1;

STATEMENT HANDLES

The statement handles of DBD::mysql support a number of attributes. You access these by using, for example,

my $numFields = $sth->{'NUM_OF_FIELDS'};

Note, that most attributes are valid only after a successfull execute. An "undef" value will returned in that case. The most important
exception is the "mysql_use_result" attribute: This forces the driver
to use mysql_use_result rather than mysql_store_result. The former is
faster and less memory consuming, but tends to block other processes.
(That's why mysql_store_result is the default.)

To set the "mysql_use_result" attribute, use either of the following:

my $sth = $dbh->prepare("QUERY", { "mysql_use_result" => 1});

or

my $sth = $dbh->prepare("QUERY");
$sth->{"mysql_use_result"} = 1;

Column dependent attributes, for example NAME, the column names, are returned as a reference to an array. The array indices are
corresponding to the indices of the arrays returned by fetchrow and similar methods. For example the following code will print a header of table names together with all rows:

my $sth = $dbh->prepare("SELECT * FROM $table");
if (!$sth) {

die "Error:" . $dbh->errstr . "\n";

}
if (!$sth->execute) {

die "Error:" . $sth->errstr . "\n";

}
my $names = $sth->{'NAME'};
my $numFields = $sth->{'NUM_OF_FIELDS'};
for (my $i = 0; $i < $numFields; $i++) {

printf("%s%s", $i ? "," : "", $$names[$i]);

}
print "\n";
while (my $ref = $sth->fetchrow_arrayref) {

for (my $i = 0; $i < $numFields; $i++) {

printf("%s%s", $i ? "," : "", $$ref[$i]);

}
print "\n";

}

For portable applications you should restrict yourself to attributes
with capitalized or mixed case names. Lower case attribute names are
private to DBD::mysql. The attribute list includes:

ChopBlanks

this attribute determines whether a fetchrow will chop preceding and trailing blanks off the column values. Chopping blanks does not have impact on the max_length attribute.

mysql_insertid

MySQL has the ability to choose unique key values automatically. If this happened, the new ID will be stored in this attribute. An
alternative way for accessing this attribute is via
$dbh->{'mysql_insertid'}. (Note we are using the $dbh in this
case!)

mysql_is_blob

Reference to an array of boolean values; TRUE indicates, that the
respective column is a blob. This attribute is valid for MySQL
only.

mysql_is_key

Reference to an array of boolean values; TRUE indicates, that the
respective column is a key. This is valid for MySQL only.

mysql_is_num

Reference to an array of boolean values; TRUE indicates, that the
respective column contains numeric values.

mysql_is_pri_key

Reference to an array of boolean values; TRUE indicates, that the
respective column is a primary key.

mysql_is_auto_increment

Reference to an array of boolean values; TRUE indicates that the
respective column is an AUTO_INCREMENT column. This is only valid for MySQL.

mysql_length
mysql_max_length

A reference to an array of maximum column sizes. The max_length is the maximum physically present in the result table, length gives the theoretically possible maximum. max_length is valid for MySQL only.

NAME

A reference to an array of column names.

NULLABLE

A reference to an array of boolean values; TRUE indicates that this column may contain NULL's.

NUM_OF_FIELDS

Number of fields returned by a SELECT or LISTFIELDS statement. You may use this for checking whether a statement returned a result: A zero value indicates a non-SELECT statement like INSERT, DELETE or UPDATE.

mysql_table

A reference to an array of table names, useful in a JOIN result.

TYPE

A reference to an array of column types. The engine's native column types are mapped to portable types like DBI::SQL_INTEGER() or DBI::SQL_VARCHAR(), as good as possible. Not all native types have a meaningfull equivalent, for example
DBD::mysql::FIELD_TYPE_INTERVAL is mapped to DBI::SQL_VARCHAR(). If you need the native column types, use mysql_type. See below.

mysql_type

A reference to an array of MySQL's native column types, for example DBD::mysql::FIELD_TYPE_SHORT() or DBD::mysql::FIELD_TYPE_STRING(). Use the TYPE attribute, if you want portable types like
DBI::SQL_SMALLINT() or DBI::SQL_VARCHAR().

mysql_type_name

Similar to mysql, but type names and not numbers are returned.
Whenever possible, the ANSI SQL name is preferred.

mysql_warning_count

The number of warnings generated during execution of the SQL
statement.

TRANSACTION SUPPORT

Beginning with DBD::mysql 2.0416, transactions are supported. The
transaction support works as follows:

o By default AutoCommit mode is on, following the DBI specifications.

o If you execute

$dbh->{'AutoCommit'} = 0;

or

$dbh->{'AutoCommit'} = 1;

then the driver will set the MySQL server variable autocommit to 0 or 1, respectively. Switching from 0 to 1 will also issue a COMMIT, following the DBI specifications.

o The methods

$dbh->rollback();
$dbh->commit();

will issue the commands COMMIT and ROLLBACK, respectively. A
ROLLBACK will also be issued if AutoCommit mode is off and the
database handles DESTROY method is called. Again, this is following the DBI specifications.

Given the above, you should note the following:

o You should never change the server variable autocommit manually,

unless you are ignoring DBI's transaction support.

o Switching AutoCommit mode from on to off or vice versa may fail.

You should always check for errors, when changing AutoCommit mode. The suggested way of doing so is using the DBI flag RaiseError. If you don't like RaiseError, you have to use code like the following:

$dbh->{'AutoCommit'} = 0;
if ($dbh->{'AutoCommit'}) {

# An error occurred!

}

o If you detect an error while changing the AutoCommit mode, you

should no longer use the database handle. In other words, you
should disconnect and reconnect again, because the transaction mode is unpredictable. Alternatively you may verify the transaction mode by checking the value of the server variable autocommit. However, such behaviour isn't portable.

o DBD::mysql has a "reconnect" feature that handles the so-called

MySQL "morning bug": If the server has disconnected, most probably due to a timeout, then by default the driver will reconnect and
attempt to execute the same SQL statement again. However, this
behaviour is disabled when AutoCommit is off: Otherwise the
transaction state would be completely unpredictable after a
reconnect.

o The "reconnect" feature of DBD::mysql can be toggled by using the

mysql_auto_reconnect attribute. This behaviour should be turned off in code that uses LOCK TABLE because if the database server time
out and DBD::mysql reconnect, table locks will be lost without any indication of such loss.

MULTIPLE RESULT SETS

As of version 3.0002_5, DBD::mysql supports multiple result sets
(Thanks to Guy Harrison!). This is the first release of this
functionality, so there may be issues. Please report bugs if you run
into them!

The basic usage of multiple result sets is

do
{

while (@row= $sth->fetchrow_array())
{

do stuff;

}

} while ($sth->more_results)

An example would be:

$dbh->do("drop procedure if exists someproc") or print $DBI::errstr;

$dbh->do("create procedure somproc() deterministic

begin
declare a,b,c,d int;
set a=1;
set b=2;
set c=3;
set d=4;
select a, b, c, d;
select d, c, b, a;
select b, a, c, d;
select c, b, d, a;

end") or print $DBI::errstr;

$sth=$dbh->prepare('call someproc()') ||
die $DBI::err.": ".$DBI::errstr;

$sth->execute || die DBI::err.": ".$DBI::errstr; $rowset=0;
do {

print "\nRowset ".++$i."\n---------------------------------------\n\n";
foreach $colno (0..$sth->{NUM_OF_FIELDS}) {

print $sth->{NAME}->[$colno]."\t";

}
print "\n";
while (@row= $sth->fetchrow_array()) {

foreach $field (0..$#row) {

print $row[$field]."\t";

}
print "\n";

}

} until (!$sth->more_results)

For more examples, please see the eg/ directory. This is where helpful DBD::mysql code snippits will be added in the future.

Issues with Multiple result sets

So far, the main issue is if your result sets are "jagged", meaning,
the number of columns of your results vary. Varying numbers of columns could result in your script crashing. This is something that will be
fixed soon.

MULTITHREADING

The multithreading capabilities of DBD::mysql depend completely on the underlying C libraries: The modules are working with handle data only, no global variables are accessed or (to the best of my knowledge)
thread unsafe functions are called. Thus DBD::mysql is believed to be
completely thread safe, if the C libraries are thread safe and you
don't share handles among threads.

The obvious question is: Are the C libraries thread safe? In the case of MySQL the answer is "mostly" and, in theory, you should be able to
get a "yes", if the C library is compiled for being thread safe (By
default it isn't.) by passing the option -with-thread-safe-client to
configure. See the section on How to make a threadsafe client in the manual.

INSTALLATION

Windows users may skip this section and pass over to WIN32 INSTALLATION below. Others, go on reading.

First of all, you do not need an installed MySQL server for installing DBD::mysql. However, you need at least the client libraries and
possibly the header files, if you are compiling DBD::mysql from source. In the case of MySQL you can create a client-only version by using the configure option --without-server. If you are using precompiled
binaries, then it may be possible to use just selected RPM's like
MySQL-client and MySQL-devel or something similar, depending on the
distribution.

First you need to install the DBI module. For using dbimon, a simple DBI shell it is recommended to install Data::ShowTable another Perl
module.

I recommend trying automatic installation via the CPAN module. Try

perl -MCPAN -e shell

If you are using the CPAN module for the first time, it will prompt you a lot of questions. If you finally receive the CPAN prompt, enter

install Bundle::DBD::mysql

If this fails (which may be the case for a number of reasons, for
example because you are behind a firewall or don't have network
access), you need to do a manual installation. First of all you need to fetch the modules from CPAN search

http://search.cpan.org/

The following modules are required

DBI
Data::ShowTable
DBD::mysql

Then enter the following commands (note - versions are just examples):

gzip -cd DBI-(version).tar.gz | tar xf cd DBI-(version)
perl Makefile.PL
make
make test
make install

cd ..
gzip -cd Data-ShowTable-(version).tar.gz | tar xf cd Data-ShowTable-3.3
perl Makefile.PL
make
make install

cd ..
gzip -cd DBD-mysql-(version)-tar.gz | tar xf cd DBD-mysql-(version)
perl Makefile.PL
make
make test
make install

During "perl Makefile.PL" you will be prompted some questions. Other
questions are the directories with header files and libraries. For
example, of your file mysql.h is in /usr/include/mysql/mysql.h, then enter the header directory /usr, likewise for
/usr/lib/mysql/libmysqlclient.a or /usr/lib/libmysqlclient.so.

WIN32 INSTALLATION

If you are using ActivePerl, you may use ppm to install DBD-mysql. For Perl 5.6, upgrade to Build 623 or later, then it is sufficient to run

ppm install DBI
ppm install DBD::mysql

If you need an HTTP proxy, you might need to set the environment
variable http_proxy, for example like this:

set http_proxy=http://myproxy.com:8080/

As of this writing, DBD::mysql is missing in the ActivePerl 5.8.0
repository. However, Randy Kobes has kindly donated an own distribution and the following might succeed:

ppm install http://theoryx5.uwinnipeg.ca/ppms/DBD-mysql.ppd

Otherwise you definitely *need* a C compiler. And it *must* be the same compiler that was being used for compiling Perl itself. If you don't
have a C compiler, the file README.win32 from the Perl source
distribution tells you where to obtain freely distributable C compilers like egcs or gcc. The Perl sources are available via CPAN search

http://search.cpan.org

I recommend using the win32clients package for installing DBD::mysql
under Win32, available for download on www.tcx.se. The following steps have been required for me:

- The current Perl versions (5.6, as of this writing) do have a

problem with detecting the C libraries. I recommend to apply the
following patch:

*** c:\Perl\lib\ExtUtils\Liblist.pm.orig Sat Apr 15 20:03:40 2000 --- c:\Perl\lib\ExtUtils\Liblist.pm Sat Apr 15 20:03:45 2000 ***************
*** 230,235 ****
--- 230,239 ----

# add "$Config{installarchlib}/CORE" to default search path
push @libpath, "$Config{installarchlib}/CORE";

+ if ($VC and exists($ENV{LIB}) and defined($ENV{LIB})) { + push(@libpath, split(/;/, $ENV{LIB}));
+ }
+

foreach (Text::ParseWords::quotewords('\s+', 0, $potential_libs)){

$thislib = $_;

- Extract sources into C:\. This will create a directory C:\mysql

with subdirectories include and lib.

IMPORTANT: Make sure this subdirectory is not shared by other TCX
files! In particular do *not* store the MySQL server in the same
directory. If the server is already installed in C:\mysql, choose a location like C:\tmp, extract the win32clients there. Note that you can remove this directory entirely once you have installed
DBD::mysql.

- Extract the DBD::mysql sources into another directory, for example

C:\src\siteperl

- Open a DOS shell and change directory to C:\src\siteperl.

- The next step is only required if you repeat building the modules:

Make sure that you have a clean build tree by running

nmake realclean

If you don't have VC++, replace nmake with your flavour of make. If error messages are reported in this step, you may safely ignore
them.

- Run

perl Makefile.PL

which will prompt you for some settings. The really important ones are:

Which DBMS do you want to use?

enter a 1 here (MySQL only), and

Where is your mysql installed? Please tell me the directory that contains the subdir include.

where you have to enter the win32clients directory, for example
C:\mysql or C:\tmp\mysql.

- Continued in the usual way:

nmake
nmake install

If you want to create a PPM package for the ActiveState Perl version,
then modify the above steps as follows: Run

perl Makefile.PL NAME=DBD-mysql BINARY_LOCATION=DBD-mysql.tar.gz
nmake ppd
nmake

Once that is done, use tar and gzip (for example those from the
CygWin32 distribution) to create an archive:

mkdir x86
tar cf x86/DBD-mysql.tar blib
gzip x86/DBD-mysql.tar

Put the files x86/DBD-mysql.tar.gz and DBD-mysql.ppd onto some WWW
server and install them by typing

install http://your.server.name/your/directory/DBD-mysql.ppd

in the PPM program.

AUTHORS

The current version of DBD::mysql is almost completely written by Jochen Wiedmann, and is now being maintained by Patrick Galbraith
(patg@mysql.com). The first version's author was Alligator Descartes, who was aided and abetted by Gary Shea, Andreas Koenig and Tim Bunce
amongst others.

The Mysql module was originally written by Andreas Koenig
<koenig@kulturbox.de>. The current version, mainly an emulation layer, is from Jochen Wiedmann.

COPYRIGHT

This module is Large Portions Copyright (c) 2004-2006 MySQL Patrick
Galbraith, Alexey Stroganov, Large Portions Copyright (c) 2003-2005
Rudolf Lippan; Large Portions Copyright (c) 1997-2003 Jochen Wiedmann, with code portions Copyright (c)1994-1997 their original authors This
module is released under the same license as Perl itself. See the Perl README for details.

MAILING LIST SUPPORT

This module is maintained and supported on a mailing list,

perl@lists.mysql.com

To subscribe to this list, go to

http://lists.mysql.com/perl?sub=1

Mailing list archives are available at

http://lists.mysql.com/perl

Additionally you might try the dbi-user mailing list for questions
about DBI and its modules in general. Subscribe via

dbi-users-subscribe@perl.org

Mailing list archives are at

http://groups.google.com/group/perl.dbi.users?hl=en&lr=

Also, the main DBI site is at

http://dbi.perl.org/

ADDITIONAL DBI INFORMATION

Additional information on the DBI project can be found on the World
Wide Web at the following URL:

http://dbi.perl.org

where documentation, pointers to the mailing lists and mailing list
archives and pointers to the most current versions of the modules can
be used.

Information on the DBI interface itself can be gained by typing:

perldoc DBI

right now!

BUG REPORTING, ENHANCEMENT/FEATURE REQUESTS

Please report bugs, including all the information needed such as
DBD::mysql version, MySQL version, OS type/version, etc to this link:

http://bugs.mysql.com/

perl v5.10.1 2010-07-12 DBD::mysql(3pm)